Does 7zip work with archive manager?
Solution 1:
Make sure the p7zip-full and p7zip-rar packages are both installed. It is particularly p7zip-rar that is needed to provide RAR extraction functionality.
You can install those packages in the Software Center, or you may prefer to install them in a Terminal (Ctrl+Alt+T) by running:
sudo apt-get update && sudo apt-get install p7zip-full p7zip-rar