To start off - are you using Firefox OS, Firefox for Andriod or Firefox for iOS - aka "Mobile Firefox" versions and using the same Sync account as with your Firefox Desktop / Laptop Firefox version/s? That combination has been causing problems for some users. ---------------------- ''The following is based upon my experiences with "Desktop" Firefox only - I have no "Mobile" devices. But Sync works pretty much the same on all "devices", but with "Mobile" having slight differences with regards to the "Toolbar".'' Sync 'runs' whenever Firefox is open. The user has no control over Sync - it's "connected" or it is "disconnected". IMO, the Sync Now button ''(if you are using it)'' is basically a 'remnant' from the previous version of Sync that was used in Firefox 28 back to the Firefox 4.0 version; ''(which did allow the user to make Sync run manually only via that Sync Now button after setting a hidden pref. That hidden pref is now gone).'' When you make any changes to your bookmarks, each change is getting sent almost immediately to the Sync server - one-change-at-a-time. Then almost simultaneously one-change-at-a-time to your other devices, when Firefox is open and "connected" to Sync on those devices. I had watched that 'process' many times with two devices sitting side-by-side; add a bookmark on one PC and watch appear a fraction of a second later on the other PC. That said ... When it comes to the Bookmarks Toolbar on the desktop ''(including laptops)'' version of Firefox, changes on those devices should stay "sync'd" properly among those devices. They use the same "Bookmarks Toolbar" arrangement. '''But''' if you have any "mobile Firefox" versions on that Sync account (where there is a difference with regards to the "Toolbar") , that might cause corruption issues on the desktop devices. I have seen many unresolved ''(as far as pinning down the exact cause)'' support threads here in the last 7 or 8 months with regards to "mobile" being used along with "desktop" devices and subsequent user reported "corruption" issues. User reports about how each user actually fixed their problem differed greatly or we never heard back that is was resolved. ''Many users didn't follow to posted suggestions for resolution or went only half way and then 'nuked' their Sync account and started over again.'' Plus, this "corruption" many times resulted in many multiple sets of folders in the Bookmarks Menu along with many multiples of the Bookmarks Toolbar folders. ''One user reported many hundreds of duplicates.'' ------------------- Let us know if you are using "Mobile" and we can give you a "plan of action" to resolve your issues.