diff --git a/CI/prepare_superbuild.cmake b/CI/prepare_superbuild.cmake
index b61877759155e263cce390f47665cb346b9fe88f..65f420c5e865e43043e544764c599a494457f242 100644
--- a/CI/prepare_superbuild.cmake
+++ b/CI/prepare_superbuild.cmake
@@ -77,7 +77,7 @@ set(CTEST_GIT_UPDATE_CUSTOM echo No update)
 
 ctest_start (Experimental TRACK CI_Prepare)
 
-ctest_update()
+ctest_update( SOURCE "${OTB_SOURCE_DIR}" )
 
 set(CTEST_BUILD_FLAGS "-j16")