Did you remove the sessionstore.jsonlz4 file and copied the previous.js file to sessionstore.js?

cor-el said

Did you remove the sessionstore.jsonlz4 file and copied the previous.js file to sessionstore.js?

Yes, but Firefox ignores it and at the next restart it recovers nothing. But you pointed me to the solution: delete not just sessionstore.jsonlz4 but all .jsonlz4 in sessionstore-backups too. Solved! Now it don't ignores the sessionstore.js :D Thx

It worked for me when I renamed the compressed sessionstore.jsonlz4 file. The devs had decided to keep the uncompressed files and made it possible to use these in case of issues as a fallback.

Note that you need to close Firefox before making changes to these files.

The sessionstore-backups folder shows both jsonlz4 versions and older .js versions of the files.

I spent some time to figure out that sessionstore.js is not converted correctly by Firefox automatically. This happened to me when I tried to upgrade from 45.8.0 to 53.0.3.

When upgrading do the following:

• Backup sessionstore-backups folder.
• Install FF.
• Remove all *.jsonlz4 files from sessionstore-backups folder as well as sessionstore.jsonlz4 from profile folder.
• Copy recovery.js from backup to sessionstore.js in profile folder.
• Start FF. Now I got session correctly restored.

I still suffer from a problem: after Mozilla crashes, it removes sessionstore.jsonlz4 and once started, the old session is not restored. I periodically get into situation that session is not restored.