diff --git a/packaging/windows/speed-dreams-base.nsi b/packaging/windows/speed-dreams-base.nsi
index fa7a13b5..e18410ab 100644
--- a/packaging/windows/speed-dreams-base.nsi
+++ b/packaging/windows/speed-dreams-base.nsi
@@ -185,6 +185,9 @@ Section "!Base System" SEC01
   ; Base tracks (only Espie)
   SetOutPath "$INSTDIR\data\tracks\circuit\espie"
   File /r /x *.lib "${BUILD_INST_DIR}\data\tracks\circuit\espie\*.*"
+
+  ; Write the install dir to the registry so that optional installs can find it.
+  WriteRegStr   ${GAME_ROOT_REGKEY} "${GAME_DIR_REGKEY}" "" "$INSTDIR"
   
 SectionEnd