We use the Windows policy “Prevent access to registry editing tools”. This blocks reg.exe, which results in winfsp not being availlable as a volume type. Can this be fixed by reading registry keys the proper way just like any normal program?
Welcome to the Cryptomator Community 
There is no fix, because this is not a bug.
I would also be careful when using words like “normal” and “proper”. When you are writing a windows native application using C# or C++, the proper way might be using the Windows API directly, because c++ or c# endpoints are offered. But Cryptomator is written in Java, therefore calling reg.exe in a subprocess and parse the result is as good as writing errorprone JNI code.
That said, it can be changed. You are welcome to open a feature request on our issue tracker.