Windows 98 build 2001

Windows 98 build 2001 is an update to Windows 98 Service Pack 1, which fixes several issues relating to the Y2K bug. While the system is referred to by the RTM build's build number, it calls itself build 2001 in some areas.

It should not be confused with various pre-release builds also branded as "Service Pack 1", which were actually Second Edition builds in the form of an update package for First Edition. Those builds also included feature and application updates not included in the final Service Pack 1, though many of these updates were later made available to First Edition users separately.