Here’s what the error looked like for me:
And the last few lines of your sync log (works only for Firefox with Sync Add-on installed, duh!) should look like the following:
A quick post on the Sync support mailing list lead me to this post which explains this is because of an upgrade to the format in which data is stored on the server. In short, the Sync Add-on will need to be upgraded whenever a change is made to the format in which data is stored online. Obviously the upgrade hasn’t become available on AMO (i.e. addons.mozilla.org) – yet.
The conclusion? You have two choices
- You choose to wait for the add-on to upgrade automatically. This is advisable if you use current versions
- Manually upgrade to the beta version of Firefox Sync (Beta 1.5 at present - here). Which you will find yourself doing if you play around with Beta versions. I also had to do this because I suddenly had a lot of changes to sync (especially passwords) :-(
In any case, this post is with the intent of bringing all of this information on a single page. Please let me know if this helped, if you found anything new or spotted any mistakes.
Useful Links (in reducing order of relevance):
- Download the current version of Firefox Sync
- Download the development (i.e. a could-break) version of Firefox Sync
- An explanation of what caused this problem
- Release notes of Firefox Sync 1.5 Beta 6 (Sept 24, 2010)
- The home page of Firefox Sync add-on
- Previous Post: Running Two Versions of Firefox At the Same Time
- My Posts About: Firefox