Have you ever get some warnings like this?

[!] <‘PBXGroup name=’Filter’ UUID=‘99CE81391BA80D2D00CA7B29’>‘ attempted to initialize an object with an unknown UUID. ‘995E161E1BAAA6C2002153EC’ for attribute: ‘children’. This can be the result of a merge and the unknown UUID is being discarded.

https://stackoverzone.files.wordpress.com/2015/10/pod-warning.png

Don’t worries, I have a solution :]

  1. Open any file by Xcode
  2. On right side of Xcode, choose Show the File inspector > Target Membership
  3. Try to uncheck and check the file on any target:

https://stackoverzone.files.wordpress.com/2015/10/screen-shot-2015-10-23-at-9-10-03-pm.png