Hmm, how odd! Somehow your DerivedData folder got moved from the default location. The default location should be /Users/<USER_NAME>/Library/Developer/Xcode/DerivedData.
You can reset it back to the default location by doing the following
- Click “Xcode” from the top menu bar
- Click “Preferences” in the drop-down menu (third from the top)
- In the Preferences window, click “Locations” (second from the right)
- In the “DerivedData” section, set this to “Default” or whichever folder path you want.
If for whatever reason, you can’t move the DerivedData folder, it’s safe to delete. The DerivedData folder is a cache of project builds and simulator data.