When Sync "gets confused" simply change your Password for Sync online here: https://accounts.firefox.com/settings

That will clear all your data from the Sync server, and as you log in to Sync again on each device. Don't rush the process as it may take some time to re-synchronize your data on the server.

When it comes to manually re-arranging bookmarks on a device, disconnect from the Sync server while you are rearranging them. Once you are done connect back to the Sync server and after 5 minutes or so restart Firefox so that Sync will do a "launch" connection to the Sync server.

Yes there are "issues" with Sync, especially when it comes to a user manually rearranging a larger number of bookmarks. Moving one or two bookmarks at a time typically is done almost immediately, but I have observed what I would call a "batch mode" where subsequent changes are delayed being sent to the Sync server and are sent later.

As far as "extensions", none that I have seen with regards to Firefox Sync; but there are alternative "sync" applications available for use with Firefox and other brand web browsers. BUT using an alternative "sync" app along with Firefox Sync seems to create another set of issues based upon support threads I have seen in this forum.

Why is there no option to clear sync data without changing password?

Mozilla need to fix a lot of bugs with sync. Until then it is better not to use sync.

This is chrome is number 1 browser. It just works without problems.

Apple has an extension on firefox that syncs bookmarks with apple hardware and safari browser.

EGC said

Why is there no option to clear sync data without changing password?

The "option" to clear all Sync data is a "backhanded option" IMO. I call it that mainly because changing the Firefox Account Password renders the data on the Sync server as a useless 'blob'. A different Password would need a different internal (on the connected devices) security key which is automatically generated from the Password, so the data is deleted from the server. The initial builds of Weave (which later became the built-in Firefox Sync service) didn't have an "option" for that and users would need to create a new Weave account using a different email address. During the pre-release testing of Weave I went thru 7 different email addresses as I was testing Weave as a mere user in 2009-2010 and I ran into issues from time to time, which I reported Bugs with Weave.

This seems / is as buggy as hell. I've been using extensively on both Mac and Ubuntu and major sub-trees have been disappearing.

I've started backing up bookmarks in git/github while I figure out an alternative or safe way to work.

PS I love Firefox in general but imho bookmark sync should be removed as a service until it works.

Most users don't have a problem with bookmarks going missing, but typically the "mobile" versions of Firefox (Firefox for iOS and Firefox for Android) are involved for many who have posted in this forum about lost bookmarks or duplicated bookmarks.

Please let Mozilla know how you feel about Sync by using the Help > Submit feedback ... menu item which leads here - https://qsurvey.mozilla.com/s3/FirefoxInput/

Whilst I'm glad that most users don't have a problem, that doesn't help this particular user. I hardly ever use Firefox on mobile, my problem (as above) is using Firefox sync with bookmarks on Mac and Ubuntu and it's unusable. I realize you're not writing fault tolerant software but "most" doesn't inspire confidence.

I have to either use unsynced browsers or switch to a browser that can do this *all* of the time ...trying out Opera now. Thanks for your reply anyway, I've reported the problem to Mozilla as above.