hello, i suspect this is a setting which is getting pushed to clients during the sync process by the server for load-balancing stuff, controlled maintenance periods, etc.

https://twitter.com/mozservices/status/373108653693235200

philipp thank you very much for taking the time to reply.

If I understand what you've said correctly, you're suggesting that Mozilla are undertaking some scheduled maintenance to servers and so are temporarily forcing users syncInterval to 12 hours?

However, having taken a look at Twitter, that maintenance and the 12 hour sync force finished over a month ago...

https://twitter.com/mozservices/status/373242687320641536

FYI also just found another report from a user experiencing the same thing:

https://mail.mozilla.org/pipermail/services-dev/2013-April/001735.html

hey, no this was only meant as an example that the sync interval is controlled by the server side (the tweet shouldn't indicate that there is an ongoing maintenance currently).

edit: but i'm not entirely sure on how that preference is intended to work and what should happen when a user sets a custom value either...

See:

• http://mxr.mozilla.org/mozilla-central/source/services/sync/modules/policies.js

Looks that is is derived from the services.sync.scheduler.singleDeviceInterval pref.

this.singleDeviceInterval = Svc.Prefs.get("scheduler.singleDeviceInterval") * 1000;
  
get syncInterval() Svc.Prefs.get("syncInterval", this.singleDeviceInterval),
set syncInterval(value) Svc.Prefs.set("syncInterval", value),

Thanks for your reply cor-el but unfortunately setting the "singleDeviceInterval" value seems to make no difference to resetting of the syncInterval, its always reset to 3600000 regardless.

This is insanely annoying, and apparently has been doing it for awhile. Firefox's sync is about a joke, I can't depend on it to sync in a timely matter, can't change the interval without being reset, none of the interface settings sync, so I have to make changes at work anytime I change them at home, this is just annoying. Chrome's syncing is awesome. I switched back to firefox because of user interface customizations, and general privacy concerns, but I'm very close to just switching to chromium. Sync is one of the biggest features a browser can have, and firefox's is a joke compared to chromes.

Sync is currently being rewritten.

• http://www.ghacks.net/2014/01/12/mozilla-plans-update-firefoxs-data-synchronization-feature-version-29/