FCPX 10.6.1 and Monterey 12.3 slow
Since Monterey 12.3 update on iMac M1, FCPX 10.6.1 is be very slow to the point it is not possible to use fluently FCPX. Have you encountered this problem?
iMac, macOS 10.13
You have that AWFUL cleanmymac thing. This is considered malware by those of us who have seen the damage it can inflict.
Absolutely, totally remove this - you will have to follow their own instructions, it is not enough to drag it to trash.
You have Chrome - it, together with its keystone daemons, is known to wreak havoc on video applications, by hogging the system videotoolbox.
See https://chromeisbad.com for a detailed explained and for instructions on how to remove them.
After removing, you will need to delete and reinstall FCP (this does not delete any of your libraries or your media, just the application).
Even after all that, we can't say for sure if there is any lasting damage from cleanmymac, so in the end you may have to do a clena install.
But for now, make a backup, uninstall cmm and chrome (and its keystone minions), delete and reinstall FCP, and let us know.
