Hi, You can try to check if this happens with other programs. eg. Internet Explorer. If there are any Windows OS tweaks applied you can also try to make adjustments in the tweaks program. Otherwise you can consider the [https://support.mozilla.org/en-US/kb/reset-firefox-easily-fix-most-problems Reset Firefox] feature via '''Help''' ('''Alt''' + '''H''') > '''Troubleshooting Information'''. (To revert to the previous profile you were using, close the new profile (i.e. exit Firefox), start Firefox and choose the '''Default User''' profile. While the [https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles Profile Manager] is open, you can also delete the newly reset profile (the one containing random numbers), or the former profile, as the case may be). If the reset is okay, it would be a good idea to delete the old profile as otherwise it would be left intact with the previous data until deleted. [https://support.mozilla.org/en-US/kb/Managing-profiles Managing profiles] [https://support.mozilla.org/en-US/kb/Profiles?s=profile&r=2&e=sph&as=s Profiles Howto]