SSD almost full

First thing to do is check the Downloads folder. I could contain many dmg files that were downloaded as part of app updates. Once the update is performed the dmg file is not needed and can be deleted. Many users have reported finding 2-3 GBs of files in the. Downloads folder that were not needed.

One way to clear our caches is the following: boot into Safe Mode according to How to use safe mode on your Mac and reboot normally.

NOTE: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

Note: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will assure a good boot into Safe Mode.

One simple way to clear many system caches is just to restart once in Safe Mode, and then restart normally again.

Also, you can always delete the user caches, under ~/Library/Caches.

Caches, by definition, are created automatically and may be recreated later, if needed.

First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This user tip describes what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is designed solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

As you're already been warned please uninstall CMM according to the developer's instructions. It is considered to be akin to malware by most around here.

OUCH!!!!

You should NEVER install "cleanmymac" or any other program that claims to clean, speed up or optimize your mac.

This one is particularly nasty. In many cases it cleans "a little too well", causing lots of trouble.

Agree. CleanMyMac is quite unsafe. I also have Malwarebytes on my M1 Mac and it run fine. However, it raraelybdetect malware or adware because I don’t normally go to suspicious websites or open junk mails, just delete them right away.

I used to installed Intego Internet Security but it is so buggy that I decide to abandon it a few years back.

You can delete caches, as they will be recreated as and if needed.

Just to make sure that there is no temporary inconsistency, I'd logout and login again immediately after deleting the user caches.