I have the same problem. I understand they're supposed to drop off after 3 weeks but mine haven't.

I had to re-setup Firefox Sync on my mobile and the old registration is still there, as you say Firefox Sync uses the same Device Name.

How do I delete old registered Sync Devices? Thanks

I have the same problem - complicated by the fact that I got a new laptop on which Firefox kept crashing and I had to restart all over - now Firefox works just fine but for the past six months or so I have had and still have about 5 duplicates of this same device with different histories. The old ones haven't dropped off and I can't find a way to delete them. There has to be a way to delete devices and leave only active ones. Can't someone from Mozilla help, please.

Annoyingly as you've found too, old devices don't disappear by themselves after a period of time.

Are you using Firefox 28 or older or Firefox 29+?

• If you're using Firefox 28 or older: You'll need to go into Firefox Sync options on a PC/Laptop and opt to overwrite the server copy with the local copy. This will wipe all previous sync data stored on the Firefox Sync Server (new and old). Then simply sync again on all your other devices to add them back in.

• If you're using Firefox 29+ - You need to delete your Firefox Sync Account and re-register. This will wipe all previous sync data stored on the Firefox Sync Server. Thankfully you can immediately re-register with the same e-mail address. Then simply sync again on all your other devices to add them back in.

There's no current way to remove old devices with Firefox 29+

I found out this workaround here: https://support.mozilla.org/en-US/questions/1003802

I had the same problem myself and can confirm this works, if a little worrying when you delete the account.

I'm using Firefox 30 - in Firefox itself (Tools-Options-Manage Account) there is no option to delete, and when I click on the link you provided I can't seem to sign in because my user name is a user name and not an email - so if I don't have an account with an email how do I sign in, and for that matter how am I still syncing. Boy am I confused.

I have tagged the question as escalate. That may result in HelpDesk or someone knowledgeable about Sync providing an answer, but that may take a few days.

Thank you so much. So now I've logged in to my old Firefox pre-29 sync account and tried to delete - asked me confirm which I did - but nothing seems to happen - and then I went to the new post Firefox 29 account page and created a new account with my email address. But nothing seems to have changed on the computer I'm using - still shows the same user name when I go to tools/options/manage account, all the five versions of my new laptop all still show up when I go to history/tabs from other devices. No idea yet whether it will have any effect on the laptop when I turn that on this afternoon. So, still confused.

You can't be running Firefox 28 (and older) Sync and Firefox 29+ Sync at the same time. You need to either have all your devices on Firefox 28 (and older) or upgrade them all to Firefox 29+ (i.e. Firefox 29 and newer).

You can't mix and match. It sounds like this is at the root of your confusion.

Firefox 28 (and older) Sync accounts are totally separate from Firefox 29+ Sync accounts.

Personally I ensured all my devices were on Firefox 30, then logged into the Old Firefox Sync site (see below) and deleted my account. I then created a new Account through Firefox 30 Sync Options.

A few days later I had to delete my new Firefox Sync account and re-register to remove some old/dead devices, as described in my previous forum post above.

Old Firefox Sync site: https://account.services.mozilla.com/ New Firefox Sync site: https://accounts.firefox.com

In Firefox 30 Sync options click Disconnect, then Manage Account. You'll then be transferred to a web page to "delete account". You should only need to repeat this process if you've got old/dead devices you wish to remove.

If you've ensured all your devices are using Firefox 30 and Sync is setup on each of them using the same e-mail address, and you still have dead/old devices showing, delete your New Firefox Sync account and start again. That should clear it.

I did have to uninstall/reinstall Firefox on my Android devices to clear off their Sync data too. Clearing Application Data would've probably been enough but to be sure I uninstalled/reinstalled Firefox 30.

The old Firefox 28 (and older) Sync engine is still online and will be for a while yet. It's there to give people time to upgrade.

Agreed Mozilla have made the whole thing overly complicated and confusing.

It took me a bit of time to get my head around, especially having to delete your Sync account just to remove old devices with Firefox 29+. I was worried I wouldn't be able to re-register with the same e-mail address but thankfully you can.

I'm not - I'm running FireFox 30 on all my devices. I went to the old site, deleted my account (which used a user name), went to the new site and create an account (which uses an email address). So why when I go to tools/options/sync does my old user name still show up? Why doesn't deleting the accounts delete all the old devices? How do we clear everything and start all over AND - Most important - if we delete everything to start all over does the sync then start with all the settings, bookmarks, etc. on the device we're creating the new account with so that it isn't lost and then syncs with the other devices when they open Firefox (and by the way - last question - how do the other devices start to sync - is there a sign on with the new account?) Sorry for all the questions.

"So why when I go to tools/options/sync does my old user name still show up?"

It sounds like you've not disconnected from the Old Firefox Sync and re-added it. The Old Firefox Sync mechanism will run happily in Firefox 30 for the time being but if you disconnect/logout etc... and re-connect/log back in you'll only be given the option to use the New Firefox sync mechanism.

That's exactly how I found it anyway.

"Why doesn't deleting the accounts delete all the old devices?"

If you've "deleted" the account it will do. It sounds like your Firefox on your PC/Laptop is still connected to the old Firefox Sync, but you said you also went to the Old Site and Deleted the Account, so I can't see how that's possible.

"Most important - if we delete everything to start all over does the sync then start with all the settings, bookmarks, etc. on the device we're creating the new account with so that it isn't lost"

Correct. That's exactly how it works. You'll possibly lose Sync Data on your "other" devices but in my case that's what I wanted to do because they contained Dead Devices.

I wanted to start fresh taking all Sync Data from my PC as the base level.

"and by the way - last question - how do the other devices start to sync - is there a sign on with the new account?"

Correct. If we're talking Firefox Mobile go into Firefox Settings and you'll see a Firefox Sync option. To be sure uninstall Firefox Mobile (Android/iOS etc...) and reinstall it. Then login to Firefox Sync on them again.

SUCCESS!!! I went to the old accounts page, deleted the account THEN unlinked the device (tools/options/sync) and then signed in with the new account - all set. Then did the exact same thing on the next device - bingo! Thank you for the help.

Yes, that is the current way to do this. Thank you for your question, I am responding to the HelpDesk request for this thread. Currently there is no manage devices feature, on this page https://accounts.firefox.com/settings there is only delete account or change password. Currently this is the meta bug for tracking this feature for remote wipe and device management on Sync https://bugzilla.mozilla.org/show_bug.cgi?id=821532 Please do not comment on this bug.