Firefox resets customization and sync information after system forcefully shut down.
I've updated my Windows 10 installation to version 1809, and it seems to frequently hang without recovery now. I've considered reformatting everything, but I can only do that when I have a backup drive ready. The issue is, if Firefox is open, and I run a forced shut down due to the hang, Firefox loses my customization settings (hotbar arrangement, theme, New Tab design, preferred search engine) and also my sync settings. I get logged out of Firefox Sync and I always have to reconfirm my login.
Firefox also displays a lot of delay when first opened, and even though pages show up as loading, they take up to 5 minutes to load, the last 4 seconds of which is actually loading the page. Firefox just stays on standby for a while.