I am deploying Firefox 10.x ESR in my organization onto computers running Windows 7 Enterprise x64. I've found that on computers both affected and unaffected by my group policy settings that after I export bookmarks from the old system and import them to the new system that within a day the bookmarks are empty. I do not have the places.sqlite file set as read only like some KB posts say to check and there are no password sync/management plugins or features being used on the workstations. I also have not determined a schedule to try to determine what frequency or event may be happening that is emptying the bookmarks. Sometimes I can close and reopen Firefox a number of times through the day and the bookmarks stay but vanish the next day, other times I close and reopen once and the bookmarks are gone. Any ideas?