Two things:
- I'm having some problems unpacking some RAR archives using The Unarchiver. It those archives that consists of serveral RAR files. It says the archive file corrupted. It works fine unpacking the RAR files with Stuffit Expander
- When unpacking the same files with Stuffit Expander it doesn't have to search for other files (or whatever The Unarchiver does, which I have to manually approve due to the sandbox)
Both applications are installed via the App Store.