I have important question, do you start Firefox with blank tab (Home tab), or Firefox starts with previous session? If you don't use session, please go to Tree Tabs settings and tick "Discard tree structure after browser's restart, this option is for those who don't use browser's session. Basically it disables loading database at startup." checkbox in Global section.

EDIT FOR RESPONSE:
Alright! I'm rebuilding some stuff at the moment and I hope session recovery will be stronger after new changes. Also I will avoid constant reloading on failure (this behavior wasn't intentional, it was supposed to reload once, stop and ask user to load backup after user clicked on the label and if Firefox loaded its windows). "tabs saved" appears on autosave, maybe I can make an option in manager window to disable it.
Nonetheless changes probably will take me few weeks to finish and bug test, since I have some problems with my car and I have difficulties with transport, what drives me nuts is in my city public transport is nonexistent... No pun intended...