--- a/suite/installer/windows/nsis/installer.nsi
+++ b/suite/installer/windows/nsis/installer.nsi
@@ -294,16 +294,22 @@ Section "-Application" APP_IDX
   DetailPrint $(STATUS_INSTALL_APP)
   SetDetailsPrint none
 
   ${LogHeader} "Installing Main Files"
   ${CopyFilesFromDir} "$EXEDIR\core" "$INSTDIR" \
                       "$(ERROR_CREATE_DIRECTORY_PREFIX)" \
                       "$(ERROR_CREATE_DIRECTORY_SUFFIX)"
 
+  ; distribution/extensions must exist for the optional extensions to install
+  ; properly. Ensure it is present on install, no harm if it is empty.
+  ; CreateDirectory creates nested dirs if required. If already present we'll
+  ; Just fix ourselves on ClearErrors below
+  CreateDirectory "$INSTDIR\distribution\extensions"
+
   ; The MAPI DLL's are copied and the copies are then registered to lessen
   ; file in use errors on application update.
   ClearErrors
   ${DeleteFile} "$INSTDIR\MapiProxy_InUse.dll"
   ${If} ${Errors}
     ; Clear the way for the new file and delete the old file on reboot
     Rename "$INSTDIR\MapiProxy_InUse.dll" "$INSTDIR\MapiProxy_InUse.dll.moz-delete"
     Delete /REBOOTOK "$INSTDIR\MapiProxy_InUse.dll.moz-delete"