If you change a file name extension, the file may become unusable.
In Solution Explorer, you are renaming a file with a different extension. This can cause problems because both Solution Explorer and Visual Database Tools use the file name extensions to locate and track certain information. If you change the file name extension, the file will probably be unusable.
To correct this error
Click No to avoid the rename process, and then enter a new name but use the existing file extension.
Click Yes to modify the file extension and potentially forfeit use of the file.