diff --git a/Docs/src/usefulfunc.but b/Docs/src/usefulfunc.but
index e2525495..23c73c09 100644
--- a/Docs/src/usefulfunc.but
+++ b/Docs/src/usefulfunc.but
@@ -532,7 +532,7 @@ There is also a copy of this macro in the Include folder, so you only have to in
 \c
 \c   !ifndef UPGRADEDLL_NOREGISTER
 \c     WriteRegStr HKLM "Software\Microsoft\Windows\CurrentVersion\RunOnce" \
-\c       "Register $R4" '"$SYSDIR\rundll32.exe" "$R4",DllRegisterServer'
+\c       "Register $R4" 'rundll32.exe "$R4",DllRegisterServer'
 \c   !endif
 \c
 \c   Goto upgradedll.done_${UPGRADEDLL_UNIQUE}
diff --git a/Include/UpgradeDLL.nsh b/Include/UpgradeDLL.nsh
index 233a6fb9..413a7011 100644
--- a/Include/UpgradeDLL.nsh
+++ b/Include/UpgradeDLL.nsh
@@ -89,7 +89,7 @@
 
   !ifndef UPGRADEDLL_NOREGISTER
     WriteRegStr HKLM "Software\Microsoft\Windows\CurrentVersion\RunOnce" \
-      "Register $R4" '"$SYSDIR\rundll32.exe" "$R4",DllRegisterServer'
+      "Register $R4" 'rundll32.exe "$R4",DllRegisterServer'
   !endif
 
   Goto upgradedll.done_${UPGRADEDLL_UNIQUE}