Hi, ya changing is a good thing. It happens a lot. I recommend it if have the time. Is there a reason you did not disconnect your devices (plural) as Sync is not a back up service and will loose your information like you did just now as it is meant to transfer data between devices.

So if you were using this as a backup service since you do not mention another device it would be best to stop now before loose critical data. If this is not the case then please continue here with following instructions Please Note Sync does not do away with doing a proper backup :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Please ignore this Support Article until you get to Create a Bugzilla Account. Then please continue to the other bold place so you can connect with a Supervisor with in a few days or sooner.

Please do not make more than the 1 message as it does not hurry the process along.

Please note : that you should explore the issues of deleting something while still using it.

Please let us know if this solved your issue or if need further assistance.

Is the problem that you can't make your secondary address primary on the Firefox Account if you lose access to the Primary? I think that is true, looking at this page that says you need to verify your primary address first:

https://accounts.firefox.com/settings/emails

Are you sure your Yahoo address is completely gone and you can't revive it in any way? According to this page, you have 30 days from deletion: https://help.yahoo.com/kb/SLN2044.html

Also, you always have the option of creating a new address for Sync. You can create an additional Outlook account (@outlook.com or @hotmail.com), a Gmail account, or even a new Yahoo account. Is that more hassle than learning a new browser?