Don't know if it's the latest Firefox or latest Windows 10 update or what but since the last Windows update happened I cannot open Firefox. I get the message "Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window." Task Manager shows 4 firefox processes including 1 crashhelper and 3 firefox approximately 70 mb, 4 mb, and 32 mb. I tried to disable the SkeletonUI by editing omni.ja but that didn't help. I tried uninstalling and that didn't help. I tried the refresh option first but ran into the same open process error so that wasn't an option. I am quite stumped. Any advice appreciated. The lock file shows up as SkeletonUILock-c388d246 in appdata/Local/Mozilla/Firefox and it disappears when Firefox is manually booted from Task Manager. It can't be examined when it's extant since it's in use by the Firefox process (presumably)