diff --git a/Tools/buildbot/external-amd64.bat b/Tools/buildbot/external-amd64.bat
--- a/Tools/buildbot/external-amd64.bat
+++ b/Tools/buildbot/external-amd64.bat
@@ -5,17 +5,17 @@
 call "%VS100COMNTOOLS%\..\..\VC\vcvarsall.bat" x86_amd64
 
 if not exist tcltk64\bin\tcl85g.dll (
-    cd tcl-8.5.9.0\win
+    cd tcl-8.5.11.0\win
     nmake -f makefile.vc COMPILERFLAGS=-DWINVER=0x0500 DEBUG=1 MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 clean all
     nmake -f makefile.vc COMPILERFLAGS=-DWINVER=0x0500 DEBUG=1 MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 install
     cd ..\..
 )
 
 if not exist tcltk64\bin\tk85g.dll (
-    cd tk-8.5.9.0\win    
-    nmake -f makefile.vc COMPILERFLAGS=-DWINVER=0x0500 OPTS=noxp DEBUG=1 MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 TCLDIR=..\..\tcl-8.5.9.0 clean
-    nmake -f makefile.vc COMPILERFLAGS=-DWINVER=0x0500 OPTS=noxp DEBUG=1 MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 TCLDIR=..\..\tcl-8.5.9.0 all
-    nmake -f makefile.vc COMPILERFLAGS=-DWINVER=0x0500 OPTS=noxp DEBUG=1 MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 TCLDIR=..\..\tcl-8.5.9.0 install
+    cd tk-8.5.11.0\win    
+    nmake -f makefile.vc COMPILERFLAGS=-DWINVER=0x0500 OPTS=noxp DEBUG=1 MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 TCLDIR=..\..\tcl-8.5.11.0 clean
+    nmake -f makefile.vc COMPILERFLAGS=-DWINVER=0x0500 OPTS=noxp DEBUG=1 MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 TCLDIR=..\..\tcl-8.5.11.0 all
+    nmake -f makefile.vc COMPILERFLAGS=-DWINVER=0x0500 OPTS=noxp DEBUG=1 MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 TCLDIR=..\..\tcl-8.5.11.0 install
     cd ..\..
 )