git rebase master
First, rewinding head to replay your work on top of it…
error: The following untracked working tree files would be overwritten by checkout:
HFFrame.xcodeproj/project.xcworkspace/xcuserdata/apple.xcuserdatad/UserInterfaceState.xcuserstate
Please move or remove them before you can switch branches.
Aborting

could not detach HEAD

Execution:

~/Desktop/HFFrame(example) $ git clean -d -fx “”