https://bugs.winehq.org/show_bug.cgi?id=39025
--- Comment #11 from Rosanne DiMesio dimesio@earthlink.net --- (In reply to super_man from comment #10)
http://source.winehq.org/git/wine.git/blob/ 797c037bff2f7621f5b3d632bd899349529d6b2b:/programs/winecfg/drive.c#l55
It's lower than that.
struct drive drives[26]; /* one for each drive letter */
There are only 26 letters in the English alphabet. Windows has the same limit on drive letters; above 26, you have to mount the volume to a directory.