Device: PC - Win7 x64 - FF v85.0 (64-bit) Also: Running latest version of Kaspersky Anti-Virus. About 6 weeks ago (or so) Firefox started acting weird on youtube. The left pop-out bar (Home/subscriptions/etc) is blank. The user account tab (shows my avatar) but when I click on it the pop-open bar is blank with a spinning arrow inside that never resolves. Therefore I can't make any changes to appearance/etc. I can't comment (Returned error). I've tried running in Safe Mode w/ addons disabled, same problem. Everything works properly if I use Chrome. <shudder> This problem doesn't occur on my laptop same SW environment, nor on my work computer Win10 - FF v85.0 (64-bit) w/ different AV (Cisco IIRC). Attempts to resolve: followed Mozilla's instructions (https://support.mozilla.org/en-US/kb/uninstall-firefox-from-your-computer) - deleted from Add/Remove Programs, deleted %APPDATA% files, even cleared all items from the registry. Did a fresh install (using a new d/l of the installer). Logged in using my firefox account & encountered the same problems. Help? Thanks in advance!