>GetVolumeInfoW ?

Wouldn't I have the same problem then when converting from an unknown doublebyte character set?

Anyway, I'm getting a sufficiently decent string. Only sometimes, when the last character of the encrypted string is a "Ď", it wouldn't stay stored in the registry, or at least was lost on read.

I just made sure we have no more unprintable characters in the strings in the registry. "Unprintable" here seems to have a very wide definition :).