Comment 13 for bug 565342

Do we want to support multiple users sharing the same prefix? I haven't seen too much about this lately, though I know in the past you could share a drive c, dosdevices and system.reg, but that the user.reg and userdef.reg had to be unique to the user. Is that still the case? If so, we could only check that user/userdef.reg are user owned/writable, but on the others, check that we have the correct permission, not ownership.