After building XEmacs-21.1.6 a couple of times I finally figured out why emacs-build-time was consistenly reported incorrect. Output from nmake /f xemacs.mak distclean contains this: del *.exe d:\tmp\21.1\xemacs\src\xemacs.exe The process cannot access the file because it is being used by another process. This is not an error under the Windows NT [Adrian scratches his head to find the right word] Operating System. xemacs.exe is silently not removed. What I'm not sure of: Is xemacs.exe correctly rebuilt in such a case? It's modification time remains that of the previous build. Dumping however, does not report an error: Dumping from d:\tmp\21.1\xemacs\src\temacs.exe to d:\tmp\21.1\xemacs\src\xemacs.exe Thanks for any insight, Adrian