Firefox used to have special sync settings where you could force override current browser with data from the server, force override other Firefox browsers with current data from Firefox you’re just using and the third one to merge them.
But Mozilla has long ago removed this and set “merge” as the default and only action.
Problem that this created was when one browser went out of sync for whatever reason and it was incredibly hard to get it back in sync with the others. You can spot such issues when one browser just refuses to get a certain add-on synced that all other Firefox clients are already using for quite a while. This most often happens if you’re testing different add-ons in one browser, adding and removing them before Firefox can actually sync properly with the server. That seems to throw off other clients out of sync quite often.
There is however a neat trick that somewhat mitigates this issue. Clients can still go out of sync, but there is at least an easy way to get them back in sync again without reinstalling Firefox which is what I used to do before…
Re-syncing Firefox browsers
Open the browser which has the desired arrangement of settings, add-ons and bookmarks. Open Options, go to Sync side tab and click Disconnect… button. Wait for a second or two and then, click Sign in button and login to your Firefox account. This Disconnect-Sign in process seems to initiate browser wide re-synchronization, resulting in all browsers connected to sync account to reacquire data from the server and they also get back in sync from that point on. It’s not as quick as it used to be, but at least it’s something.
In theory, this should work if you do it on whichever system, but I’ve tested it with the one that had the desired arrangement of data that I wanted to transfer to other clients.
I hope this will save you guys some time and nerves. 🙂