I get the "BASE SDK Missing" when re-opeing projects. (I got the latest build of xcode, and latest SDK installed.)
It seems to be happening when I quit a project, (not exiting xcode), and re-open the project after a while. I have tried both, with and without my iPhone plugged in. I have tried to fix the problem like described here, but it does not help for me. - It just makes it even worse! (unrecognizable SDK)
The only way I have managed to get it back to normal, is to do a manual re-boot of my mac, plugged in my phone, waited until it has checked my iPhone, and then, opened xcode. Time consuming and annoying!
Why does it happen and what is the trick to fix this?