I got a new laptop in early August, and I installed Firefox and started Sync up (it was already working on the old laptop). It seems to have worked all right for a couple weeks, but just now I discovered that each laptop doesn't have anything in the History that I did on the other one since August 15 at 15:08. I've just found that in Settings there's a list of things that get synced, and "History" was not in the list. I've now added it, but why did it work for a couple weeks and then stop?? How can I prevent this happening again? Can I get them to sync back to August 15? I started another thread in early August (https://support.mozilla.org/en-US/questions/1345759) about another problem with Sync. That one was not completely resolved.