Windows XP build 2197 (main.000106-2102)

Windows XP build 2197 (main.000106-2102) is the earliest known build of Windows XP, compiled in early 2000. It was mentioned in an IT Pro article from 13 February 2000, where Paul Thurrott claimed that build 2197 was the first internal build of Whistler and that it had gone out internally "weeks ago".

This is confirmed by the Windows XP source code leak, where the build's full build tag is referenced in comments located in :

This build tag was much longer than prior versions of Windows, adding the lab, compile date, and compile time to the end of the build string after the compile number. All versions of Windows after this kept this extended build tag.