My sync was working beautifully for years. Yesterday I updated to 29, Firefox tells me to update to the new sync system. I follow their instructions and do so. Now all I get is "Sync encountered an error while syncing: Unknown error" continually. I assume its being overwhelmed with all the clients updating so I waited till today, but I am still getting the error. I am unable to understand the log file, I don't see where the error is happening. All I am syncing is tabs and history, that's it. I have deleted the contents of the "weave" folder and that didn't help. Is there another place to clean up? Thank you for any help! Here is the log: 1398834367908 Sync.ErrorHandler DEBUG Flushing file log. 1398834367910 Sync.Status DEBUG Status.service: error.sync.failed_partial => success.status_ok 1398834367925 Sync.ErrorHandler DEBUG Log cleanup threshold time: 1397970367925 1398834367925 Sync.ErrorHandler DEBUG No logs to clean up. 1398834369190 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834372539 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834374204 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834376220 Sync.Tracker.History DEBUG Saving changed IDs to history 1398834376710 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834378074 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834379213 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834381747 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834384255 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834386766 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834389270 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834391769 Sync.Tracker.Greasemonkey DEBUG Saving changed IDs to greasemonkey 1398834392372 Sync.Status DEBUG Status.service: success.status_ok => success.status_ok 1398834392411 Sync.ErrorHandler DEBUG Beginning user-triggered sync. 1398834392417 Sync.Service DEBUG User-Agent: Firefox/29.0 FxSync/1.31.0.20140421221237. 1398834392417 Sync.Service INFO Starting sync at 2014-04-30 13:06:32 1398834392418 Sync.SyncScheduler DEBUG Clearing sync triggers and the global score. 1398834392418 Sync.Status INFO Resetting Status. 1398834392418 Sync.Status DEBUG Status.service: success.status_ok => success.status_ok 1398834392418 Sync.BrowserIDManager DEBUG _ensureValidToken already has one 1398834392709 Sync.Resource DEBUG mesg: GET success 200 https://sync-4-us-west-2.sync.services.mozilla.com/1.5/204187/info/collections 1398834392709 Sync.Resource DEBUG GET success 200 https://sync-4-us-west-2.sync.services.mozilla.com/1.5/204187/info/collections 1398834392710 Sync.Service DEBUG Fetching global metadata record 1398834392710 Sync.Service DEBUG Clearing cached meta record. metaModified is 1398834291.09, setting to 1398834368.21 1398834392710 Sync.BrowserIDManager DEBUG _ensureValidToken already has one 1398834393013 Sync.Resource DEBUG mesg: GET success 200 https://sync-4-us-west-2.sync.services.mozilla.com/1.5/204187/storage/meta/global 1398834393013 Sync.Resource DEBUG GET success 200 https://sync-4-us-west-2.sync.services.mozilla.com/1.5/204187/storage/meta/global 1398834393014 Sync.Service DEBUG Weave Version: 1.31.0 Local Storage: 5 Remote Storage: 5 1398834393014 Sync.Service INFO Sync key is up-to-date: no need to upgrade. 1398834393014 Sync.Service DEBUG Fetching and verifying -- or generating -- symmetric keys. 1398834393014 Sync.Service INFO Testing info/collections: {"forms":1398834094.13,"tabs":1398834367.61,"clients":1398833648.99,"crypto":1398801208.09,"reqpolsync":1398801243,"stylishsync":1398801230.47,"meta":1398834368.21,"history":1398802640.26} 1398834393014 Sync.CollectionKeyManager INFO Testing for updateNeeded. Last modified: 1398801208.09 1398834393014 Sync.Synchronizer DEBUG Refreshing client list. 1398834393014 Sync.Engine.Clients INFO 0 outgoing items pre-reconciliation 1398834393015 Sync.Engine.Clients INFO Records: 0 applied, 0 successfully, 0 failed to apply, 0 newly failed to apply, 0 reconciled. 1398834393015 Sync.Synchronizer INFO Updating enabled engines: 2 clients. 1398834393015 Sync.EngineManager DEBUG Could not get engine: stylishsync 1398834393015 Sync.EngineManager DEBUG Engines are: ["bookmarks","forms","history","passwords","prefs","tabs","addons","greasemonkey","adblockplus"] 1398834393015 Sync.EngineManager DEBUG Could not get engine: reqpolsync 1398834393015 Sync.EngineManager DEBUG Engines are: ["bookmarks","forms","history","passwords","prefs","tabs","addons","greasemonkey","adblockplus"] 1398834393016 Sync.Engine.Forms INFO 0 outgoing items pre-reconciliation 1398834393017 Sync.Engine.Forms INFO Records: 0 applied, 0 successfully, 0 failed to apply, 0 newly failed to apply, 0 reconciled. 1398834393017 Sync.Engine.History DEBUG First sync, uploading all items 1398834393024 Sync.Status DEBUG Status for engine history: error.engine.reason.unknown_fail 1398834393024 Sync.Status DEBUG Status.service: success.status_ok => error.sync.failed_partial 1398834393024 Sync.ErrorHandler DEBUG history failed: database disk image is malformed No traceback available 1398834393025 Sync.Engine.Tabs INFO 1 outgoing items pre-reconciliation 1398834393025 Sync.Engine.Tabs INFO Records: 0 applied, 0 successfully, 0 failed to apply, 0 newly failed to apply, 0 reconciled. 1398834393058 Sync.Engine.Tabs INFO Uploading all of 1 records 1398834393058 Sync.BrowserIDManager DEBUG _ensureValidToken already has one 1398834393059 Sync.Collection DEBUG POST Length: 8912 1398834393374 Sync.SyncScheduler DEBUG Next sync in 600000 ms. 1398834393429 Sync.Collection DEBUG mesg: POST success 200 https://sync-4-us-west-2.sync.services.mozilla.com/1.5/204187/storage/tabs 1398834393429 Sync.Collection DEBUG POST success 200 https://sync-4-us-west-2.sync.services.mozilla.com/1.5/204187/storage/tabs 1398834393430 Sync.Synchronizer INFO meta/global changed locally: reuploading. 1398834393430 Sync.Service DEBUG Uploading meta/global: {"id":"global","modified":1398801243.24,"payload":"{\"syncID\":\"LWdt41J03mmA\",\"storageVersion\":5,\"declined\":[\"greasemonkey\",\"addons\",\"adblockplus\",\"prefs\"],\"engines\":{\"clients\":{\"version\":1,\"syncID\":\"yaaCJts8zJjH\"},\"forms\":{\"version\":1,\"syncID\":\"1ihmOD9OxTge\"},\"history\":{\"version\":1,\"syncID\":\"Mwy4odUVKI7g\"},\"tabs\":{\"version\":1,\"syncID\":\"OXXkM_KyPEXD\"},\"stylishsync\":{\"version\":1,\"syncID\":\"anfkHR8jD-4x\"},\"reqpolsync\":{\"version\":1,\"syncID\":\"pWKKESI5VrkR\"}}}"} 1398834393431 Sync.BrowserIDManager DEBUG _ensureValidToken already has one 1398834393438 Sync.Resource DEBUG PUT Length: 524 1398834393727 Sync.Resource DEBUG mesg: PUT success 200 https://sync-4-us-west-2.sync.services.mozilla.com/1.5/204187/storage/meta/global 1398834393727 Sync.Resource DEBUG PUT success 200 https://sync-4-us-west-2.sync.services.mozilla.com/1.5/204187/storage/meta/global 1398834393727 Sync.Synchronizer INFO Sync completed at 2014-04-30 13:06:33 after 1.31 secs. 1398834393727 Sync.Declined DEBUG Handling remote declined: ["greasemonkey","addons","adblockplus","prefs"] 1398834393727 Sync.Declined DEBUG Handling local declined: ["greasemonkey","addons","adblockplus","prefs"] 1398834393728 Sync.Declined DEBUG Declined changed? false 1398834393728 Sync.Service INFO No change to declined engines. Not reuploading meta/global. 1398834393728 Sync.SyncScheduler DEBUG Next sync in 600000 ms. 1398834393729 Sync.ErrorHandler DEBUG Some engines did not sync correctly.