The value of the vbld_FormatDateTime system script function will change every second, and if the LOGFILE macro references these, since they are evaluated each time the macro is referenced, that will be a problem (the log filename will change every second).
To use the starting date+time value for the log filename for the entire build, assign the expanded value to a temporary LOGFILE macro in the project's vbld_BuildStarting script event:
Code:
Function vbld_BuildStarting()
' remove temp macro in case it already exists (to avoid recursion)
vbld_TempMacros().Remove "LOGFILE"
' store the expanded value of the current LOGFILE project/global macro
' (possibly containing a date+time value) so that the log filename
' will remain the same for the entire build
vbld_TempMacros().Add "LOGFILE", Application.ExpandMacrosAndScript("%LOGFILE%")
End Function
http://www.visualbuild.com/Manual/scriptevents.htm