Compiler Error CS2033

Cannot create short filename 'filename' when a long filename with the same short filename already exists

Compile any C# file with a name longer than eight characters. Then compile another file with the short version of the preceding file name, such as the first six characters of the name plus "~1." The second compile will generate this error.

To resolve this error, rename the short file name to one that does not conflict with the long file name.