Debian Tor Browser Showing a Black Screen
Answer form Debian bugs tracker : bug #942901
edit your /etc/apparmor.d/local/torbrowser.Browser.firefox
and add the following line:
owner /{dev,run}/shm/org.mozilla.*.* rw,
Also add exactly the same line to /etc/apparmor.d/local/torbrowser.Browser.plugin-container
. Then:
sudo systemctl restart apparmor
The Debian bug tracker states:
Message #5
Tor Browser 9.0 shows only black screens because the default apparmor profile does not allow write access to /dev/shm/org.mozilla.ipc.. like it does for /dev/shm/org.chromium.* and I was able to fix this issue by adding this workaround:
==> /etc/apparmor.d/local/torbrowser.Browser.firefox <==
owner /{dev,run}/shm/org.mozilla.*.* rw,