Compiler Error CS2021

File name 'file' is too long or invalid

All file names passed to the C# compiler must be no longer than _MAX_PATH (defined in a Windows header file). The compiler will give this error in the following situations:

• A file name (including the path) is longer than _MAX_PATH.

• The file name contains invalid characters.

• The file name contains wildcards where wildcards are not allowed (such as in resource file names).