Entitlements file was modified during the build

I fixed this with Product > Clean Build Folder.

Ran into the same issue. You can set CODE_SIGN_ALLOW_ENTITLEMENTS_MODIFICATION as a User-Defined setting in Build Setting.

• In Xcode click on your project target and click Build Settings.
• Click the "+" underneath Build Settings and then "Add User-Defined Setting"
• Set CODE_SIGN_ALLOW_ENTITLEMENTS_MODIFICATION to YES for debug and release (or whatever schemes you like)

Before you start modifying the build settings you can also try deleting the Derived data in your install or build directory. If the project cache is found in /Users/your_user_name/Library/Developer/Xcode/DerivedData/Path_To_Project/ you can do an xcode clean and it will get rid of this data. If you defined your own install or build paths then go to that specific directory and delete that cache. Xcode should provide you the path if that error happens.