After some digging, this is a bug in QLockFile. It doesn't take process name into account. So if the pid for the session.json lockfile is re- used (easy to do after a reboot), it will act like the session file is still valid.
Qt trunk fixes this (http://code.qt.io/cgit/qt/qtbase.git/tree/src/corelib/io/qlockfile_unix.cpp?h=dev). So it's just a matter of updating Qt (or backporting the patch). ** Summary changed: - Isn't remembering old session tabs + QLockFile won't notice if the lock pid is re-used by an unrelated process ** Also affects: qtbase-opensource-src (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to webbrowser-app in Ubuntu. https://bugs.launchpad.net/bugs/1500444 Title: QLockFile won't notice if the lock pid is re-used by an unrelated process Status in qtbase-opensource-src package in Ubuntu: New Status in webbrowser-app package in Ubuntu: New Bug description: My desktop webbrowser-app instance no longer seems to be remembering the previous session tabs and opening them at startup. I don't see any output on the console. Any tips for helping debug this? To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qtbase-opensource-src/+bug/1500444/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp