XPCom stores pathnames in the registry. Non-7bit ascii characters (option characters on the Mac, for example, such as a bullet) in paths are rejected by libReg.

#3690 is related. but once you fix this I will make sure there is no other problem with #3690.

The libreg API is UTF-8. If you use 7-bit ascii you're OK because those happen to be the same, but other than that you have to encode the characters. If this is the problem you're having you'll know because there is a specific error that rejects key and property names that contain bad UTF data. If that's not the problem then I need more information. The one exception is FILENAMES, which must be stored as REGTYPE_FILE data and takes a C-string in the OS character set.

Marking Verified/Won't Fix.