Misconception

• W2K is not a recognized file extension. It is a universally recognized computer acronym. W2K can be easily misidentified as a file extension due to its length of three characters, a common file extension length.
  
  

Actual Meaning

• W2K stands for Microsoft's Windows 2000 operating system. Windows 2000 is no longer supported by Microsoft as of July 13, 2010.
  
  

Custom File Extensions

• W2K could be used as a file extension for a customized purpose. There is nothing to stop an application developer or computer user from naming a file with a W2K extension. It would not likely be universally accepted due to its long-standing use as an acronym.