Fix error :Unable to generate a temporary class (result=1). error CS2001: Source file ‘C:\WINDOWS\TEMP\file.cs’ could not be found error CS2008: No inputs specified

When a service in ASP.Net is executed the error:

Unable to generate a temporary class (result=1). error CS2001: Source file ‘C:\WINDOWS\TEMP\filename.cs’ could not be found error CS2008: No inputs specified

can occur.

The problem are the permissions on the C:\WINDOWS\TEMP folder.
To fix it, give the user of the Application Pool full control on that folder.