Hi. Here's how it happened. I've using FF portable for a long time. I recently updated from v.69.0.1 to v.78.0.2. But the newer version installed in a different folder and now I can run both versions. Yesterday I had the v.69 working with around 500 tabs open. Suddenly it crashed and then freezed. Luckily, I had managed to save my current working session by accessing Tab Session Manager addon. But when I go to Tab Manager Session and click to open this saved session, FF v.69 will keep freezing, no matter what I do. (Tab Session Manager has another option „Export”, but I don't know to use it or what it does.) I will quit using FF v.69. But how can I get the new v.78 to open this 500-tab session? Any help is appreciated. Thanks.