Like tptacek said, versions of Windows after Windows XP shipped with their own disk encryption functionality. XP needed TC for that. Next to that: the announce

Like tptacek said, versions of Windows after Windows XP shipped with their own disk encryption functionality. XP needed TC for that. Next to that: the announcement to discontinue the product was very close to the MS end-of-life announcement for XP. Remotely related is the difficulty researchers had compiling TC from source and matching the official binaries. The original devs used Visual C++ 1.52 (1993) leading some to believe that the build system for TC still ran on Windows XP and was not up-to-date enough anymore.