same here MacBook Pro 2016 with a Samsung 4k monitor no matter the connection (display port hdmi) it stopped working and of course in another Macbook 2016 with Big Sur the external monitor works

I deleted parallel and the virtual windows to free space but macOS didn't free up the space until I followed the method bellow from a link That link and I regained 130 gb Open the Terminal application in Applications/Utilities. What we need to do is to start making a file that will grow until the disk is full. So enter the following into the Terminal window: dd if=/dev/zero of=~/stupidfile.crap The command will create a file called stupidfile.crap in your Home directory and fill it with zeros. It will continue to grow, first at a fast pace, but as the disk get’s close too full, it will become slower and slower. But hang in there. During the creation of the file, you will get a lot of warning messages that the disk is full. Just leave it there, because if you close it, it will reappear after a while. When the Terminal window command ends with the message “No space left on device,” the disk is full, and mission accomplished. Mac OS should now have removed all the Purgeable space from the drive. So all that is left is to delete the file stupidfile.crap inside your home directory. Don’t forget to empty the trashcan to regain the space.

the problem is with the start page... shift opening and going to another page is a "fix", something in the start page leads to crash