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My Mac is acting weird, now what?

If a Mac isn't working, the first step is to determine if it's a software or hardware problem. In the first case, some bits and bytes (that's what computer data is made of) are confused. You can fix this yourself. Software problems are therefore not covered by the warranty.
In the second case, something in the machine is physically broken. That is a job for the Apple techie.
In the subchapter Hardware Problems, however, you will find hardware-related things that you can do yourself.

Owners of M1 Macs (2021)
Your Mac should be treated slightly differently than older Macs. MacMiep has indicated this in gray areas.

Software or hardware?
Rest assured, 99 times out of 100 it is a software problem. Apple makes reliable machines. So assume that and don't immediately think that your Mac is broken. Always start with the simplest solution: Occam's Razor.

Note: Sometimes the boundary between hardware and software problems can be crossed. Bad RAM (working memory) can be the culprit. Usually you will find out soon after you insert new memory.

But first, the most important tip of all, intended for every computer user (regardless of the operating system):

How do I backup my Mac easily?
Making backups is very easy with Time Machine. Backup is fully automatic and very simple with an external hard drive. MacMiep therefore strongly advises you to purchase an external hard drive. Nowadays you can even find them at the supermarket, so excuses no longer exist. And in any case - a lot cheaper than professional data recovery and even cheaper than the most expensive of all: annoyance ....
More about this in the making backups chapter.

Avoid problems: stay up to date
It is important that you let the App Store do its work. It checks daily for updates for MacOS or apps.
Important system and program updates are downloaded in the background. You hardly notice this. You will automatically receive a notification that there is an update:

And also in the Dock:

You can find the system update settings in System Preferences => Software Update:

When you tick 'Automatically keep my Mac up to date' you will automatically receive a message that it needs to be restarted.

Use anti-malware software
Unfortunately, bad software for the Mac is out there. Anti-malware is therefore not an unnecessary luxury. MacMiep itself uses the excellent Malwarebytes. It checks your Mac for bad software.
It is wise to let it run regularly. It is not (yet) necessary to run it 24/7 in the background, but at least make sure it is on your Mac. If Apple's own SIP (System Integrity Protection) is missing something, then you have something at hand. A nice idea. More about nasty software in theMalware chapter.

I have lost my login password
When you use the wrong password 3x during login, MacOS will ask you for your Apple ID. With this you can reset your account password. So it's smart to also remember your Apple ID *.
* Make sure you have ever linked it to your account (as explained in chapter The User).
Otherwise it will not work!

If you have forgotten everything, you will have to take your Mac identification and original purchase receipt to an Apple Store (that is not your dealer). Ask first if they can help you!

View log files
UNIX, the base that is under the hood of MacOS, keeps a close eye on events within the system. You can view these 'log files' in the Console utility:

Most things won't ring a bell, but you may be able to find out what the culprit was from the time of day by Google'ing the term on the Internet.
Or you can go to a forum for help and advice from fellow Maccers.

Help my Mac is crashing!
System crashes are a rarity under MacOS. What can happen is that once a program stops responding at all (for example with an ever-spinning beach ball). You can force quit by choosing Force Quit from the Apple menu (Command + Option(Alt) + Esc).
Yes, those are three keys at the same time.

A simple Restart can do wonders. Also found in the Apple menu (along with 'Force Quit').

Throw away preferences
Sometimes a program continues to act weird, even after a restart. What you can do is to delete the so-called Preferences of that program and then restart the Mac.
Each program saves them on closing and opens them again on startup. If it contains errors, the same error will occur after a restart. Close the program, discard it and reboot.

The Preferences folder
These can be found in the Library folder in your Home folder, but with one caveat:
The Library folder folder is hidden by default.
You can reach it with a trick:
Hold down the Option (Alt) key and go into the Finder via the menu Go to the Library folder:

The Library folder
A new Finder window will open with the Library folder displayed. You should have the Preferences folder from there.

Preferences have .plist after their names. Just look for the right one.
Here in the picture the one from the Dock:

Now drag 'preference.plist' to your Desktop.
Restart the Mac and test if the problems are resolved.
If so, you can permanently delete the preferred file.

If it does not work, or if the settings of your program are messed up, restore the file and overwrite the new one.

Discard Finder Preferences
If your Finder or your Dock makes difficult, you can also throw those preferences away.
Restart the Mac afterwards to see if your action has been successful.

Note: If you, for example, discard your Dock preferences, you will have to put your own stuff in the Dock again after logging in. Some programs also store their serial numbers in it. This may also be the reason that Apple has hidden the Library folder. It is therefore better not to immediately discard the preferences, but to move them to your Desktop. This way you can always restore the original.

Reinstallation of a program that behaves not the way it should
If after discarding its preferences it does not work with an individual program, you can decide to reinstall it.
If available, first use an un-installer (a program supplied by neat programmers to completely remove the software from your Mac). Otherwise, you 'drag' the program and - importantly - its preferences to the Trash yourself.

Maybe you need an update?
Also pay attention to the version of the program you are using. An update (or upgrade) may help to cope with the problems. Visit the site of the manufacturer to see if your version of program and MacOS can work well together.
NOTE: There are programs that are very sensitive to MacOS system upgrades or updates. Music software, for example. In such a case, keep an eye on the manufacturer's site for correct system requirements, etc., in order to continue to ensure correct operation.

The 'Other User' test
You can test whether the problem is within the general operating system MacOS or whether it has something to do with your personal (program) settings. Log in as a different user.
You can read how to create this in the extra chapter User => Users.

My Mac is slow
This can have several causes. First the simplest:
- Do you also have too many programs open?
- Too many windows / tabs open in your browser?
- Hundreds of loose files on your Desktop?
- Not enough working memory (RAM) due to too large or too many files open? Working with video or large photo files, for example, requires a lot of RAM. Memory pressure can be seen in Activity Monitor Utility.
- A slow (USB 1.0) or nearly broken external hard drive? You will notice this especially when opening and saving files, when the Finder must actively access this drive. You often hear it wake up (except SSDs, which no longer rattle).
- Spotlight is still indexing (usually happens after a clean install)?
This is temporary, the search function on your Mac must first know where everything is.
- Slow startup can be due to many 'Open after login' programs, or leave 'Open windows again at login again' checked
- Do you sometimes run outdated software, or software with an error that uses up too much RAM? The latter can be seen in the Activity Monitor Tool.
- External drive that does not handle Sleep properly or is breaking down?
- Network disk (NAS) that is behaving badly?
- When was the last time you performed a reboot?
- Hard disk filled up?
Keep at least 5% free! Your working memory (RAM) also uses a piece of HD. This is called 'Swapping'. Since an HD is slower than RAM, your Mac can become slower as soon as a lot of RAM has to be used.
How much memory (RAM, hard drive) does my Mac have?
In chapter About your Mac you learn how to find that out.
- SSD disk on the full side and not original from Apple / installed yourself? You will then have to 'Trim' it yourself. Original Apple discs are automatically trimmed by MacOS.
- Have you been too enthusiastic with cleaning software? No CleanMyMac or MacKeeper or the like use. Not necessary!
- Questionable quality anti-virus software installed? Some anti-virus apps are constantly running in the background and checking everything that is happening. This can really slow down your Mac if they are poorly written.
- Accidentally caught malware?
Run regularly MalwareBytes to check if you have not contracted anything.

Insight into memory usage
To see who is doing what on your Mac, you have Activity Monitor Tool. It gives you insight into how much memory a program occupies at that moment. Invisible 'processes' are also shown:

CPU: The central computing unit (processor) of your Mac.
Who puts the most strain on it:

Memory: Which Program Uses the Most RAM?
Energy: which process uses a lot of electricity?
Disk: tells you how full the hard disk is and what
Network: View your network usage.

All of these things affect the speed of your Mac.
If you have an extremely high usage culprit, discard the program's preferences (as described earlier in this chapter).
If that doesn't help, reinstall or update the program. Check the manufacturer's website for info. Is the program compatible with your (new) MacOS? Or is there another problem going on.

My Mac remains slow

'The spinning beachball' keeps busy:

Installing a "clean system", i.e. reinstalling macOS, can work wonders. Explanation follows, first a warning:

Cleaning software: not necessary
Beware of programs that claim to clean your Mac! You don't have Windows (anymore)!
They can cause more problems than they occur. Examples of these programs are CleanMyMac and MacKeeper.

Why does MacMiep warn about this?
MacMiep warns because it regularly receives panic emails from Mac users who have installed these programs and then encounter serious problems.
Programs that stop working because they miss files, edited photos that have disappeared, missing foreign languages and fonts, or a system that just wants to boot in English.

Why is it sometimes advised and do you even get a discount?
There are websites that (for a fee?) Recommend the use of this software. It would speed up your Mac by deleting caches and log files. A lot of hard disk space would also be saved by removing unnecessary languages.
It is called "10 to 20 GB hard drive profit".

More space on my hard drive: yes nice!
Ten to twenty GigaByte could still yield something in the case of an older MacBook with a small SSD hard drive, but since most Macs HDs come with at least half a Terrabyte, so that's peanuts.

Ask yourself:
Do you want to put the wellbeing of your Mac in the hands of such a program for 2% hard drive profit?

Self-cleaning Mac
In addition: MacOS is a UNIX system. All UNIX versions have self-cleaning capability. This means that cashes and log files are handled daily, weekly or monthly by so-called cron scripts.
Read more about the myth of the "Dirty Mac" here: http://www.thesafemac.com/the-myth-of-the-dirty-mac/
This article is years old, but still valid.

The real reason why these programs exist
According to MacMiep, the makers of these types of programs have entered the Apple market because of the many switchers. Switchers are people who switch from Windows to MacOS. These people are usually used to using such programs for their PC. And the manufacturers of the Mac versions cleverly respond to this. Apple's are expensive computers, so the owners will all be rich stinkers. So cash register, that's what it's all about.

How do I keep my Mac clean?
With a soft, lint-free cloth. And the vacuum cleaner with hairbrush for the keyboard. And glass cleaner for the screen (without alcohol).

Defragmenting a hard drive is in principle not necessary under MacOS, although there is software available that does it. Hence, heated discussions can arise on Mac forums about whether or not to use it.
iDefrag is one such program. Macers who regularly work with very large files, especially video, might benefit from it.

Important: ALWAYS make a recent backup BEFORE you defragment (Time Machine).
If the power goes out during defragmentation, your entire hard drive can go wrong!

Kernel Panic: The big Crash
When MacOS has completely lost it, you can see a black area with texts appear.
This is now a real "Kernel panic".
Unfortunately, there is no other option than to follow the advice and hold the on / off button for 10 seconds.
Kernel panics are rare. Try to find the problem in software before you start with hardware.

Eternal spinning beach ball / the Mac no longer responds to anything
First check whether the batteries of your Mouse or Keyboard are empty.
Just give your Mac a few minutes to fix the problem on its own.
If nothing works anymore, press the on / off button for 10 seconds and the Mac will turn off.

Safe Boot, first choice at trouble
After such major crashes and also after a power failure, it is always wise to do a so-called Safe Boot, in other words:

A safe start-up: the first choice for MacOS problems. Start up the Mac with the Shift key held down. Automatic login will be disabled (password!) And you will see safe boot in the login screen. This so-called Safe Boot forces the system to check the file system of your boot disk. The startup therefore takes longer than usual. It also leaves third-party Kernel Extensions out of the equasion. If the problem is cause by one, it should not occur with a Safe Boot.

M1 Macs (2021)
Press and hold the Power button for ten seconds until you get this image:

Click on the hard drive and hold down the Shift key for Safe Boot.

Restart the machine in the normal way afterwards!
Not everything will work correctly after a Safe Boot, because MacOS excludes non-essential things like Wifi.

The Recovery partition on the hard drive
During the installation of MacOS, a small, invisible partition is created on your hard drive. This partition contains data for testing, repairing and reinstalling MacOS. The latter is done over the internet.

Boot from Recovery partition
1. Restart the Mac with Command-R pressed. This means that you will boot from the hidden Recovery partition. MacOS Recovery will appear:

M1 Macs (2021)
Press and hold the Power button for ten seconds until you get this image:

Click on 'Options' to be able to choose Recovery.

MacOS utilities
After booting from recovery partition, you will get into macOS utilities. You have a few options here:

- Restore from Time Machine backup
- Reinstall MacOS
- Search help information online
- Disk Utility

We'll start with Disk Utility: test the Hard Drive
A typical (not full-SSD) hard drive is a mechanical device that has to work very hard. Hard drives can fail. To see if that's the case, use Disk Utility as well.
This program checks a number of things:
1. the file system on your HD.
2. the so-called S.M.A.R.T.status * of your HD. You can find that at the bottom of the window:

* Self-Monitoring Analysis and Reporting Technology. Many hard drives have a chip on board that checks the physical state of the disk. So this tells you whether or not the disk has gone to its Grandma.

Testing a hard drive with Disk Utility

Select the problem disk and choose 'First Aid':

Note: Disk Utility does not do strange things with disks. If recovery is unsuccessful, the program will indicate this nicely and will not force anything.

First aid doesn't help
If Disk First Aid cannot repair you have a real problem. Most likely your hard drive is dying.

Let's hope you have a recent backup !!!

You can then do two things:
1. No backup? Try to repair the disk with third-party software (for example, Disk Warrior). You'll need another Mac for that and use 'Target Mode' (explained later in this chapter).
2. Best solution: erase the disk completely and then reinstall MacOS new and place back you backupped data => explanation follows.

Note: Erasing an external hard drive can always be done with Disk Utility. But the disk that your system is on, your startup disk, can only be erased when your Mac is booted from Recovery.

Extended testing of a Mac hard drive
A somewhat more extensive program for testing hard drives is DriveDX. It can tell you much more than Disk Utility:

My hard drive is okay, but my Mac remains unstable / slow
What you can do now is install a new, operating system.
This means that you put a new MacOS system on the hard disk.

Installing a clean system
What you are doing is replacing your operating system: a fresh "clean" MacOS.
The user folders and your settings will remain.
Your personal data is therefore retained.

Still, it's wise to back up first! Chapter Backup your Mac.

Reinstallation of macOS WITHOUT data loss
First, your Mac has to boot from MacOS recovery disk. Restart the machine with the Option (Alt) key pressed. Choose Reinstall MacOS.

A totally new system after installation
Now you have a completely fresh MacOS. This should fix the issues.

I am using Time Machine
Good for you! Have you backed up your entire system and data on an external hard drive thanks to Time Machine? Neat!
Did that backup from BEFORE the problems start?
That is very nice, because now you can simply restore this backup in its entirety and that saves you a lot of work.

Restore from Time Machine Backup...
You don't have to install a completely new system now, just copy the old one back.
Boot from Recovery and under the Utilities menu, choose Restore from Time Machine Backup ...
Follow the instructions on the screen and (very important) choose the correct restore dates in terms of date and time!

NOTE: It depends on the speed of the connection to the external hard drive and the amount of data how fast you can go back to work.

Help! I don't have a Recovery partition
Macs can also work without Recovery partition. To do this, connect your Mac wired to your modem / router. Wifi is also allowed (WPA2 minimal), but pulling a wire is much more stable and faster.

MacOS Internet Recovery
Boot with Command-Option(Alt)-R and Internet Recovery will appear after a while.
You will see a spinning globe on your screen:

Your Mac calls home for help
The Mac will now contact Apple servers directly to download a recovery partition and place it on your hard drive. This may take a while, depending on the speed of your internet connection.
Then your Mac boots from that partition and you have the macOS Utilities at your disposal. You can reinstall MacOS from there, but you can also restore your Time Machine backup.

So: Mac OS Internet Recovery works exactly like Command-R, but with a roundabout way.

M1 Mac: start up Internet Recovery

Pressing and holding the boot button for ten seconds on an M1 Mac produces this screen. Click on the HD to continue, or choose Options to start up the Mac over the Internet.

Booting into Internet Recovery is also not working
Then you try to boot from another external drive containing MacOS.
Note: if you have an M1 Mac, Command Option R will not work!

Boot from another startup disk
Do you have another disk with MacOS on it?
Restart the Mac with the Option (Alt) key pressed. You will now see all possible startup disks. Choose the one you want to boot from:

Boot from USB stick
Sometimes booting in Recovery Mode doesn't work. For example when your Mac is too old for that. Then you can boot from USB stick and install a fresh MacOS.
It is wise to make such a stick before hand.

Making a bootable MacOS USB stick
What you do is download a macOS installer suitable for your Mac. Then you use Terminal commands to make a bootable USB stick.
Apple tells you all about it here: How to create a bootable installer for macOS.

Older MacOS systems
Some older MacOS X systems won't install from Recovery. Something that has to do with old certificates. Then you need to do the USB stick trick too. Here you can find the older systems for download: Older MacOS X systems.

Nothing helps! What now?
- Won't the hard drive be repaired?
- Does your Mac continue to behave badly, even after installing a 'clean system'?
- Are you going to sell your Mac?
- Are you just in the mood for a severe spring cleaning?
Then there is no other option than to erase the hard disk and put everything back on it.

Total erase and installation: WITH LOSS OF ALL DATA
We are going to erase the entire hard disk. This is only necessary when Disk Utility or other recovery programs are no longer able to repair, or when you are going to sell your Mac and value privacy. Back to factory settings!

Note: This is a horse remedy and will almost never be necessary.

Total wipe and installation :
Boot from MacOS Recovery with Command-R pressed when you turn on your Mac.

M1 Mac: start up from Recovery

Pressing and holding the boot button for ten seconds on an M1 Mac produces this screen. Click on the HD to continue, or choose Options to start up the Mac over the Internet.

Now go to Disk Utility and select 'Erase'.

Choose APFS if you have an SSD or Fusion hard drive at 'Format'.

Erasing options
You can do this in several ways:

- APFS is Apple File System. This is very suitable for SSD (Solid State Drive) drives and Fusion drives (mixed SSD and mechanical). If your Mac has such an SSD or Fusion drive, choose APFS.
- Mac OS Extended is HSF +. This system has been around since 1998 and is not very suitable for SSD and Fusion drives.
- MS-DOS (FAT) is the Windows system. Files can be up to 4 GigaByte in size.
- ExFAT is also for Windows.
- Journaled means that the disk keeps a log file that remembers what happens to the disk.
- Encrypted means that the hard disk is protected with a login name and password. If someone removes the hard drive from the Mac, they cannot read anything without the Mac itself.

Windows systems format hard drives in NTSF.
Disk Utility can't do anything with that. Mac OS can only read, not write to such a disk.
If you want that (useful with BootCamp), use the Microsoft NTSF for Mac software from Paragon software.

Wipe your hard drive extra thoroughly - as a test or for your privacy
This can be found under Security options. If your hard drive had problems, choose the 'Most Secure' option. This will take a long time, but it is a good test for your HD. A disc that doesn't want this anymore is really dead.

I want to sell my Mac
Extra strong erasing is also useful if you sell your Mac. Then you bet higher and choose the Most Secure option. This will take long.
See also the chapter Security => Privacy.

Do not disturb the Mac while erasing and always keep MacBooks on their power adapter.

You can also divide the drive into partitions if you prefer. This can be found under the Partition tab.

Hard disk GUID format
Should you choose to partition your hard drive, remember that macOS always requires a 'GUID partition Map' to boot from.

Of course MacOS also supports 'RAID': a number of hard disks are virtually merged into one large hard disk. This method is widely used in servers and NAS (network drives). You can find it under the Menu File => 'RAID assistant ...':

"Do you already have a Mac?"
After the complete deletion and installation of MacOS, you will automatically be presented with this question. It's like you bought a new Mac. When you have a Time Machine backup - as a smart Maccer does - you can use it to restore your old data. This also saves you a lot of work. It is not difficult, it is precisely explained what to do.

Finally: the Help function
MacOS and most applications have plenty to say under the Help menu. Enter a search term and Help will work for you.

Online Apple help forum
Apple Support does not only help you with your Mac, but also with all other Apple products.

Know what Mac you have before asking questions
It's important to tell the helpers on the Forum the kind of Mac you own and which MacOS it is running. You can find out in this chapter: About your Mac.

A handy little program that tells you everything about your Mac is EtreCheck. It constructs a text file which you can copy to a forum or for a helpdesk. With that they have all the information they need.

Apple startup screens
You may encounter various startup screens on your Mac. Here's what they all mean:

Mac does not start, the 'thermometer' stops:

Possible Solutions:
First, give your Mac some time. Then turn it off by pressing the Power button for a few seconds.
The Mac will shut down. Now power up the Mac again with the Shift key pressed. This will cause the Mac to do a 'Safe boot'.
Does this not work?
Then turn it back on with Command-R to boot from Recovery. Use Disk Utility to repair the hard disk first and then try again. If that doesn't help, install a clean MacOS.

Folder with question mark: no MacOS system can be found:

Possible Solution:
Boot from Recovery, check the HD and install a new MacOS if necessary.

No parking: the MacOS system on this Mac is not suitable for this Mac:

Possible Solution:
Boot from Recovery, check the hard drive and install a new MacOS if necessary.

Globe: the Mac boots from internet recovery:

This may take a while, depending on the speed of your internet connection!

Globe with exclamation mark - internet recovery not working:

Possible Solution:
Try connecting your to your modem with UTP ethernet cable. It is also possible that the internet or the Apple servers are down. Then try again later.

Thunderbolt, USB or FireWire icon displayed:
Your Mac will boot into Target Mode. It will now act as an external hard drive for another Mac.

Apple on Target mode: https://support.apple.com/en-gb/guide/mac-help/mchlp1443/mac

Not intentional? Turn off with Power button.
Intentional? Now turn on the other Mac. That Mac will see yours as an external hard drive.

M1 Mac: hard drive with options

Pressing and holding the boot button for ten seconds on an M1 Mac produces this screen. Click the HD to continue, or choose Options to restore the Mac.

A lock on the Mac:

First enter a Firmware password before the Mac can start. You cannot enter this Mac without that password. Lost the password? Too bad!

PIN code in the picture:
Your Mac has been locked remotely with Find My Mac.

Enter PIN, log in to iCloud.com on another device to unlock this Mac or - in case you stole it - return it neatly to its owner and start saving money for your own Mac!

Gray screen or I don't feel like it today:

Possible Solution:
Restart from Recovery and test the hard drive and install a new MacOS if necessary.

More info on Apple startup screens.

The next chapter is:
making backups

hardware trouble

Disclaimer: MacMiep is independent. This means she writes what she wants, based on 30 years of Mac-experience. She doesn't get paid for stories (positive or negative) on this website. MacMiep is not interested in your data. However, she does use Google's services. Google is indeed interested. Are you happy with MacMiep? Please support your local cat shelter.