I sync 2 desktop installations. One is on Mac OS X 10.6 Snow Leopard, the other on Mac OS X 10.8 Mountain Lion. Both use the same latest Firefox version 16.0.2. The former syncs properly, the latter does not (also in older versions). Although the 10.8 computer appears to be syncing properly, I keep getting this error message after each restart of Firefox: "Sync encountered an error while connecting: Incorrect name or password. Please try again." I have tried these options: - cancel the message by clicking the cross "x" - re-enter the password (http://support.mozilla.org/en-US/kb/firefox-sync-troubleshooting-and-tips#w_how-do-i-resolve-an-incorrect-name-or-password-error - unlink the device and link it again - remove any Firefox setting in ~/Application Support (as if I did a clean install) None of these seem to fix the problem. It is persistent. I found an article that said how to see the sync log: http://philikon.wordpress.com/2011/06/13/how-to-file-a-good-sync-bug/ I canceled the error message and forced a sync. Error. I have even tried to delete my Sync data and to reset my key. Both did not have any success. You can find the sync password and the sync key in the password manager on the computer where you originally created that sync account (email). Look for: chrome://weave (Mozilla Services Password) chrome://weave (Mozilla Services Encryption Passphrase) Both entries are available. I had already checked this. I do not have any other problems with signin in to websites. As mentioned before, I have completely deleted my profile (and any other configuration item) by deleting any Firefox related file and folder in ~/Application Support I am not sure if this problem is Mac OS X related since I have read a similar post: https://support.mozilla.org/nl/questions/940524 I have completely removed Firefox from my system and reinstalled it. Immediately after initialising Sync, I get the error message again. Something is definitely wrong with Sync. I have tried to use a simple unsafe password (only 9 random characters from a-z). This did not solve the problem either. I have noticed something else. After the error message "Sync encountered an error while connecting: Incorrect name or password. Please try again." I click the Preferences button and try to enter the password. Clicking the button will show an error message "Wrong password. Please try again.". When I enter click the button a few seconds later, the password is accepted.

error log of a sync

Possibly related bug: 806494 https://bugzilla.mozilla.org/show_bug.cgi?id=806494

If the error message appears, you do not need to re-enter your password. Just select Sync Now from the Tools menu. After a few tries it will eventually sync and the yellow bar at the bottom of the screen will disappear.

Additional info. The computer that is causing problems is a MacBook Air running from SSD. Could it be that it is too fast for FF?

This is likely bug 798430. Please try Firefox 17 or newer (currently Firefox Beta) and let us know if the problem is fixed.

It looks like Firefox beta 17.0b3 does not cause the problem anymore.

Yay! Closing bug as duplicate then.