Unity Build Issues

Hey,

I've briefly worked with Vuforia before and work with Unity a lot but this one has me stumped, I had my whole project working on PC, but couldn't export it for iOS, realised you can't do that and moved it to a Mac and tried to build and run from there, still doesn't work. So then I tried making a new Unity project, importing Vuforia from the Asset store and nothing else, just building one of the Sample projects, and it works sometimes. Generally it seems to work once per project and then starts throwing the error below, this isn't solved by closing Unity, closing XCode, deleting the DerivedData folder or even by restarting the Mac, at least not consistently.

Unity seems to be the cause of the issue because a 'build failed' notification comes up from XCode while Vuforia is running its linker, but there's no error messages within Unity saying anything went wrong and the only XCode build issue shown is the one below.

I really hope there's a simple answer to this one that I'm just missing, help of any kind is much appreciated, I've tried looking through here and not found anything like this so far:

Unity: OS X 5.5.0

iOS: 10.2

XCode: 8.2

[quote]ld: can't open output file for writing: /Users/administrator/Library/Developer/Xcode/DerivedData/Unity-iPhone-fqfjddrffxdlricyonokdawudsoe/Build/Products/ReleaseForRunning-iphoneos/Vuforia.app/Vuforia, errno=21 for architecture arm64clang: error: linker command failed with exit code 1 (use -v to see invocation)[/quote]