Why are we getting ".XML.OLD" files when compiling?

Question

A large number of our projects (all of which have XML documentation turned on) generate <assemblyname>.XML files (as expected) and ALSO a copy of that file called <assemblyname>.XML.OLD

Not all of our projects which have XML documentation turned on generate this ".XML.OLD" file, but many of them do. There seems no rhyme or reason why some do and some don't...

Does anyone know why this is happening? And how to stop it happening?

This is with Visual Studio 2012. I also have Resharper 8 installed (a colleague has resharper 7, but still sees the ".xml.old" files).

Answer 1

This occurs when you are using Code Contracts and you have selected the option to Emit contracts into XML doc file.

I expect that the Code Contracts rewriter is simply making a backup of the XML doc file because it is changing it.