I've been googling many answers to this question, such as the various suggestions up and down https://askubuntu.com/a/202020/99436, and none of them are working for me. They might work for you. They don't work for me. The system blinks, icons on the launcher appear and dissapear, and I have to log in again - after that, it's still borked, just like before. I'm up to date as per
sudo apt-get update && sudo apt-get dist-upgrade
Unity Tweak Tool is basically not functional. As I change settings, maybe 1 in 5 of them actually do anything. Clicking reset on individual pages doesn't reset anything (nothing actually changes on the screen, or in the system).
I've lost all the icons on the bar across the top of the screen - no network, sound, clock, username, the little cog. There's nothing up there. it's just grey. No amount of unity tweak resets brings them back for my user. They are all there and working on the logon screen. But for my user? Nothing.
Can I reset everything to how it was before I installed the horrible system trashing unity tweak tool? it's really frustrating that all the previous "reset" tools have been slowly removed, or that to reset one app I have to install and run some other app.