If this has happened to you multiple times there is likely an external process running on your system that is deleting browser data files. Do you run a disk cleaner, by chance?
Unfortunately extensions cannot guard against external processes that delete local browser data. The only solution is to store data in the cloud, which is a feature we're working on. Automated backup to local files outside the purview of the browser is not possible due to browser security restrictions.
If this is a case of an external process deleting data, the data can be repaired. Copy/paste the attached code into the
Session Buddy console and hit Enter. This will report any data inconsistencies and repair them. Please share a screenshot of the console after running this code and we can go from there.
As an aside, detection and repair of this type of data corruption will be automated in the forthcoming release.
Hans