Oops, Installed and ran Clean My Mac

I read that the program deletes important protected files

What you're missing there is the word "may"... in improperly used it can do a lot of damage. But I would first wait and see if any damage has been done - oh, and delete the app per the maker's instructions.

Never install any app that claims to "tune up", "speed up" or "clean up" your Mac.

These apps exist for one reason: to separate the unwary and inexperienced user from their hard-earned money.

At best they do very little, at worst, they can damage your OS installation and cause far more problems than they "solve".

As others have already mentioned

There are those like myself, when I see the infamous Disk Cleaner has been used on this poor machine

This will include CleanMyMac , aka “ BrickMyMac “

Use Disk Utility to erase a Mac with Apple Silicon

Then start over.

This time, leave the Disk Cleaners or Third Party Security Software Off this computer

It might remove files needed to support other apps but it can't remove system protected files. As long as you use their instructions to remove CleanMyMac, it will properly remove all of it. When I had it installed, I used its own built in removal tool to remove it and that removed all of it.

AbLe66 wrote:

After installing and running a trial version of Cleanmymac I read that the program deletes important protected files. To avoid future problems, can a Mac 13 inch M1 2020 be restored to what it was before running Cleanmymac.

Just uninstall it and you should be fine. Clean My Mac has a bad reputation on this forum, but I know of many, far more reputable, apps that cause far more problems than Clean My Mac.

To put the CleanMyMac is context and the damages it may or has done.

This application can or will Muck Up your User Account ( Home Folder ) of this machine.

It does not touch the Operating System itself unless you consider your User Account ( Home Folder ) as part of the Operating System

Then in that specific context - it has Mucked Up the Operating System