FAQ #13543, published on 2016-10-06
How to cope with Xcode 7 error "Could not find Developer Disk Image"
This error will occur in Xcode 7 when testing a WINDEV Mobile 21 application on an iPhone or iPad with IOS 10 installed.

There are two ways to cope with this error :

1. Use Xcode 8 instead. This requires a WINDEV Mobile Upgrade available here

ftp://ftp.pcsoft.fr/wx21_65s/us/windevmobile/WM210PACKUSIOS065s.exe

2. Tweak Xcode 7 to make it compatible with IOS 10 devices as explained here

http://stackoverflow.com/questions/37945376/use-xcode-7-with-ios-10
See also : Xcode, IOS, 10