Before I switched to Sierra, with various previous OSX versions, I would occasionally get beachballs which I could fix by force-quitting the unresponsive application, which is usually Safari. Now with Sierra, whenever I get a beachball, the whole computer becomes unresponsive so I can't force-quit anything. I have to shut down the computer manually by holding down the power key. Also, sometimes when I start it up again, it is unresponsive at the login screen. I have to shut it down and try again. This costs me a bunch of time and I lose things I was typing, I have to go back and find what files I had open, and such. I have a lot of stuff on disk-images on external drives, so the OSX feature that opens all windows that you had before shutting down does not work for those. With previous versions of OSX everything worked great and I could go for months without rebooting. Now it's happening at least twice a day, so my computer has become more than 100 times less reliable than it was. This is is not acceptable! I expect better from Apple. I have a backup from before I installed Sierra, but that was months ago so I would lose a bunch of files and things if I restored from that. It would be a huge pain to try to manually transfer the files I need, and I would lose bookmarks and things like that. Is there anything I can do?