IOS Interface Builder is unable to determine the type of Xxx.xib/xxx.storyboard

The morning project appeared, "Interface Builder was unable to determine the type of Xxx.xib" error
SVN escalation Conflict (conflict), Xib file Burst red

Depressed

Baidu Google Stack did not find the answer

So only, drink milk to study
The xib is an XML file,

So right-click Openas Source Code
See Source code
Open and see the suspect.
There is a conflict under the root tag, so the "= = =" is deleted. "Extra content at the end of the document at 331Line" error after deletion
Found 331 rows, is the last line of the XML file, the error says "There is superfluous content"
Go back to the location where you just deleted the conflict, found that there are two root tags, exactly the same content, XML tags only allow one end, so try to delete a
Compile, OK

The previous night just upgraded the Xcode and Mac system, should be the upgrade system conflicts

IOS Interface Builder is unable to determine the type of Xxx.xib/xxx.storyboard