User Agent: Mozilla/5.0 (Android 6.0.1; Tablet; rv:55.0) Gecko/55.0 Firefox/55.0 Build ID: 20170803202939 Steps to reproduce: Upgrade from FF 54.0.1 to FF 55 on 2 devices (about 50 tabs opened when I was on FF 54.0.1) Actual results: Only one of them is restored Expected results: All the tabs I had when I was on FF 54.0.1 should be restored after the FF 55 upgrade. This is the first time it happened to me after an upgrade! Is the anyway to recover those tabs after this upgrade if we don't launch firefox (waiting a new Firefox release which would fix this issue)? Or those tabs are lost even if we don't launch Firefox ? Generally speaking, the tabs restoring on Android was not as handy as it is on Windows platform for example. As a strong feature request: is it possible to have an "restore previous session" option somewhere in order to have something equivalent to what we have on Windows platform ? Or to have access to session.js or something like that on android platform ?

This bug is quite important I think: have reproduced it ? Quite easy ! Pre - requisite : FF 54.0.1 installed Open 10 tabs on 10 different web sites Upgrade to FF 55: only one tab remains :-(

I didn't notice any problems in upgrading, but if you think you can reproduce this, can you please turn on full logging by enabling "consoleservice.logcat" and "browser.sessionstore.debug_logging" in about:config (needs a restart to become effective) and then get a log as soon as you encounter this again? You can either connect your phone to a computer and use ADB (https://developer.android.com/studio/releases/platform-tools.html, https://developer.android.com/studio/command-line/adb.html#Enabling) with the following command line: Windows > adb logcat -dv threadtime | findstr Gecko > log.txt Linux/Mac > adb logcat -dv threadtime | grep Gecko > log.txt or you can try installing the Log View add-on (https://addons.mozilla.org/android/addon/logview/) and then attempt using that to get a log if this behaviour happens again.