Cannot restart Mac, Finder issues in El Capitan

Solution 1:

My issue turned out to be in an outdated Wacom driver. After removing it, Mac worked fine. I guess formatting would have sorted it out too.

Solution 2:

To re-run Finder, try:

launchctl stop com.apple.Finder
launchctl start com.apple.Finder

Then try to run it as: open -a Finder.

For further troubleshooting, you can run the app in the foreground and check for any errors:

/System/Library/CoreServices/Finder.app/Contents/MacOS/Finder

Consider also checking the logs via log stream command. Also, disconnect any external drives to be sure (e.g. diskutil umount force /Volumes/MyDrive).

If you suspect any damaged files, it's good to rsync above files from another working macOS or try to reinstall.