In my case there were two, one in each of the 32- and 64-bit folders: um3ex_w81d_v101/Files/64bit/Files/RDIF1058.INF and um3ex_w81d_v101/Files/32bit/Files/RDIF1058.INF Search the folder and sub-folders for an *.inf file.Extract the contents its own new folder (um3ex_w81d_v101, in this case).
It's worth a try before you junk or ebay the unit which I was about to do. However there is a workaround that people have used with V-Drums and it worked for my UM-3EX too, although it takes a little editing and bypassing certification. Attempting to install with compatibility settings, admin privileges, etc.
