It's a great addon and a must have if you have almost 3000 tabs open (discarded though) most of the time right in front of you (just don't ask me why, I have a habit of going through things slowly)... It was working fine in both auto-save and timeline fields until recently... Right after the late ff84.0 update, it started to crash my browser and suck up all the memory that my system have (it's a bit older of a laptop, 16gb to be precise)... Even if it saves sessions smoothly whenever I do it manually, when I try to delete previously saved sessions it does the same thing... I tried almost everything I know like removing all the duplicates in bookmarks or setting it up to auto-save less frequently but nothing worked, and yeah I don't wanna lost all my tabs over this issue, but I don't wanna give up on this great addon either so... If there's anyway to fix this please do it... Right now I have to rely only on the timeline feature of it which I'm thankful that it exists even it has it's flaws... But I want to use this lifesaver of a software in all it's peace of mind again...