Fixing Firefox's Session Restore After Restart

Firefox doesn't seem to respect the "open previous windows" setting when the browser is closed for a restart. As someone who likes to start from a clean slate, this was frustrating me quite a bit. I decided to fix it the hard way.

Tabs Restoring is a Known Bug in Firefox

There is a bug report in Mozilla's tracker describing this exact issue. inexplicably, however, the bug is closed as "invalid" with a comment that describes the issue, but provides no workaround or justification for the behavior, instead simply stating why the bug happens.

Automatically Deleting Previous Sessions on Startup

I decided to fix this myself, admittedly in a hacky way. What I did is create a service that runs on startup and deletes the previous session store files. This is potentially dangerous, so proceed at your own risk, but it works for me at the time of writing.

The session store files are located in Firefox's profile directory, which can be found by going to about:support. Using the directory in that, the find command can be used to delete files within any profiles' sessionstore-backups folder. I am running Fedora/Linux, so mine is located in $HOME/.mozilla/firefox. The following code should be modified to match your system directory:

find "$HOME/.mozilla/firefox" -path "*/sessionstore-backups/*" -type f -print -exec rm -f "{}" \;

All you need to do is put this in a bash script to run at Startup. In Fedora/linux, this can be done with a systemd service:

[Unit]
Description=Delete Firefox Sessions

[Service]
Type=oneshot
ExecStart=/bin/bash -l -c 'exec "$@"' _ find "$HOME/.mozilla/firefox" -path "*/sessionstore-backups/*" -type f -print -exec rm -f "{}" \;

[Install]
WantedBy=default.target

Other systems may follow the same pattern in whatever startup mechanism they choose, so long as the script is run before Firefox launches.