Updated to version 12.4.1.6 and went to update my apps but keep getting this error.
iPad Air, iOS 8.3, iPad Air 2
I don't know. You could try using Edit > Preferences > Advanced > Reset Cache and/or delete the contents of the Download folder that you'll find inside the iTunes Media folder. Does either help, or does the problem persist?
tt2
I have the same problem with error 11503. It is preventing me from updating the Apps. 12.4.3.1 is the current. There are not files in the Download folder for iTunes, and I have Reset the cache, but the problem persists. Tried to update each App separately and it would seem to be hit or miss, few were able to be updated but most generate that error.
Very bizarre and very frustrating.
I found a hint somewhere that it might help to turn off simultaneous downloads, but if you update one app at a time then you're doing the same thing manually. Try Fix unexpected quits or launch issues in iTunes for Windows - Apple Support. Launch iTunes in its own safe mode one time to see if that helps any.
tt2
What is error code 11503 and how does it get fixed?
