Won't Append to Xcode Project! WHY!

I’ve had this issue twice in the past few weeks, with a project that has lots of plug-ins with weird XCode issues. When it happens, it means lots of stuff can break and I have to delicately figure those issues all over again.

I have not changed anything in the project in Xcode, and have been only doing minor script fixes in Unity. If this happens, why can’t Unity tell us EXACTLY what the problem is, so I can not freaking do it again, or I can fix it?

My project does not have multiple targets and Xcode is definitely the same version as it has been, so what could I possibly have done to piss off Unity so that it refuses to append to my Xcode project?

Biggest WTF I’ve seen in a while somehow fixed the project. Thought I should post the answer to possibly save someone else’s sanity (or my own if I forget):

In the XCode project, I keep seeing extra frameworks added as references. (AdSupport and StoreKit in this case). Didn’t seem to cause a problem so I left them alone. On a whim, I deleted them just now and tried to rebuild the project in Unity. Suddenly Unity doesn’t think anything is wrong with the XCode project (and will therefore Append it).

No idea what is going on, but it works now.