Actually, to be honest, I don’t think it’s frozen, just very slow… As mentioned, there’s a performance issue with selecting many files from Windows Explorer. This affects all such operations: encrypt/decrypt/wipe/rename .
If you can check, open up Task Manager. You should see an AxCrypt process appearing and disappearing there for a while, and then the operation started.
However, AxCrypt should not freeze during this – it should essentially not notice, although the Windows Explorer extension may behave strangely since it’s busy with this.