Found in the weekend my P.C. suddenly wouldn't detect my 1D3 tethered/connected via USB.
After going out & buying another cardreader I looked online for solutions & found that "download and install the "Media Feature Pack for N and KN versions of Windows 10" which will install the MTP driver : https://www.microsoft.com/en-us/download/details.aspx?id=48231" seemed to be the fix.
Lord knows why it suddenly stopped working (camera just continuously said "busy" when connected) but appears that installing the MS Media Feature pack has got it working again.
Good stuff, plus I've now got a cardreader that I may even use... 


