> Task: checkIntegrity
+ The places.sqlite database is sane
+ The favicons.sqlite database is sane
> Task: checkCoherence
+ The database is coherent
> Task: expire
+ Database cleaned up

This can occur when Firefox has lost access to the Places database (a pair of files that store URLs, visit history, bookmarks, and site icons). '''''In case this was caused by a locked file:''''' You can try the following: (1) Exit/Quit Firefox and after 30 seconds or so start it back up again. (2) Do a normal shutdown and/or restart of your system. Restarting Windows can help by freeing up locked files, completing any deferred updates, and resolving temporary file permission issues. (3) For nerdier users: I found a post describing how to use Windows' Resource Monitor to try to figure out what program has opened a "handle" on the file (filter by ''places''): https://superuser.com/a/643312 '''''Check for a corrupted file:''''' If that didn't help, could you let us know what you get when you run the "Verify Integrity" diagnosis and repair function. That's here: Open Firefox's Troubleshooting Information page using any of these methods: * "3-bar" menu button > Help > More Troubleshooting Information * (menu bar) Help > More Troubleshooting Information * type or paste '''about:support''' in the address bar and press Enter Near the bottom, there is a section titled '''Places Database''' -- that's the file which stores history and bookmarks. Click the button labeled '''Verify Integrity'''. There may be a 10-15 second delay before results appear. If all is well, the report that appears below the button should start with: > Task: checkIntegrity + The places.sqlite database is sane + The favicons.sqlite database is sane > Task: checkCoherence + The database is coherent > Task: expire + Database cleaned up ''et cetera'' Does yours say the databases are sane and coherent, or something else? You can select and copy the report, and then paste it into a reply for review and comment.