How to fix this? Retry/retry all didn’t helped.
@fnkr Please send your logs to support@insynchq.com for investigation: How to find the log files. You can compress them before sending to save space.
@fnkr I have deleted your post since the file is publicly accessible and might contain sensitive information.
Do the errors still persist if you restart Insync? If so please send support@insynchq.com a copy of the folder ~/.config/Insync/dbs while Insync is stopped for investigation. Please don’t post the public link again in the forums.
The logs/sqlite-db did not contain any sensitive information, I checked that before uploading them 
Anyway. here is a Google Drive shared folder shared with support@insynchq.com.
https://drive.google.com/a/fnkr.net/folderview?id=0B54LYU6_cHkhflBnbm1fSVowSHI0T18waFpQUk9DS0VNYnktV1VxUUlfaFdwU3dfVEVXcGc&usp=sharing
@fnkr Please share a copy of the folder ~/.config/Insync/dbs as well while Insync is stopped. You can compress it before sending to save space. Thanks.