xCode: Could Not Find Developer Disk Image

I’m getting this error when I attempt to sideload my Codea app onto an ipad. A Google for this says the problem is a mismatch between operating system versions and xCode versions. Operating systems on both MacBook Pro and iPad are up-to-date as is xCode. Has anyone else encountered this? Thanks.

My Bad, maybe. The MacBook wasn’t upgraded to El Capitan, but was up-to-date on the previous OS. I’m upgrading now. Nothing like posting a problem to make the answer jump out at you.

That proved to be the problem!