So lately I have been struggling with Sonarr and Radarr grabbing results that end up containing Rar files and interrupting that sweet sweet automated flow. After a good amount of searching, I found a quick working trick to allow qbittorrent to automatically unpack rars after downloading.
7zip needs to be installed. You could potentially replace that with your favorite flavor of unpacker. If you use a docker container, i believe the linuxserver qbittorrent container comes with the “unrar” package by default?
In Qbittorrent, open settings and go to the download tab. Scroll all the way to the bottom and check “Run external program on torrent completion”. For my Windows VM with 7zip installed, I input:
"C:\Program Files\7-Zip\7z.exe" e "%F\*.rar" -o"%F\" (Include all quotes)
This seems to be working for me so far. All of the downloads appear to be getting unpacked and imported so the automated flow is now uninterrupted. If you have this installed on linux, you will need to replace that with linux cli specific commands for 7zip (p7zip).