diff --git a/pre-inst-env.in b/pre-inst-env.in
index cd4ee01497..15a48dedaa 100644
--- a/pre-inst-env.in
+++ b/pre-inst-env.in
@@ -31,7 +31,7 @@ abs_top_srcdir="`cd "@abs_top_srcdir@" > /dev/null; pwd`"
 abs_top_builddir="`cd "@abs_top_builddir@" > /dev/null; pwd`"
 
 GUILE_LOAD_COMPILED_PATH="$abs_top_builddir${GUILE_LOAD_COMPILED_PATH:+:}$GUILE_LOAD_COMPILED_PATH"
-GUILE_LOAD_PATH="$abs_top_builddir:$abs_top_srcdir${GUILE_LOAD_PATH:+:}:$GUILE_LOAD_PATH"
+GUILE_LOAD_PATH="$abs_top_builddir:$abs_top_srcdir${GUILE_LOAD_PATH:+:}$GUILE_LOAD_PATH"
 export GUILE_LOAD_COMPILED_PATH GUILE_LOAD_PATH
 
 # Define $PATH so that `guix' and friends are easily found.