I tried uninstalling and loading factory settings. Whenever I open my Preferences -> Addons window, I get a blank screen. Help I cant use addons on this machine anymore. It happened after installing a supposedly 2.8 compatible addon.
In addition to second part of @rjg's answer:
Do not touch Blender installation directory. All user settings and addons stores in user AppData folder.
Try to rename "C:\Users@username@\AppData\Roaming\Blender Foundation\Blender\2.80" folder to "2.80 backup" and restart Blender.
Fresh folder 2.80 will be created. If there are no global problems with the system - everything should work fine
When missing UI elements happens, then you will see most likely a error message in the console. This error message will tell you the exact trouble maker, including path of the python script. And then you can delete or fix it.
At Windows the console can be opened from the Window menu. At Linux the system console is used. The Linux version of Blender does not have this menu item.
There are two options that you could try.
The Factory Startup
The first would be to start Blender from command line with the
--factory-startup which should prevent the broken add-on to be activated on startup.
- Open the Windows Explorer Win+E
- Navigate to the installation directory of Blender 2.8. You should see the
blender.exein the folder.
cmdin the path field and press enter. The command line prompt should open.
.\blender.exe --factory-startupon the command line and press enter
Blender should now start with the factory settings and you should be able to open the add-ons section of the preferences. Find the broken add-on in the list, open the detail section and click on the
Manually Removing an Add-on
You should only use this approach if the first one didn't work, either because the add-ons are still not listed or there is no remove button for the add-on. If the former occurred, please report this on Blender's bug tracker (Help > Report a Bug). The latter will happen if you manually copied the add-on files to the add-ons directory instead of installing it through the UI.
If you know what files have been installed with the add-on you can remove them manually. Do not remove any files if you're not 100% certain that they are part of the problematic add-on. The add-on should be installed in one of the following subfolders in Blender's installation directory:
You can simply delete the broken add-on files and it should be working again.