diff --git a/builtin-commit.c b/builtin-commit.c
index 90200ed643..a33f43a209 100644
--- a/builtin-commit.c
+++ b/builtin-commit.c
@@ -502,7 +502,8 @@ static int prepare_to_commit(const char *index_file, const char *prefix)
 
 	fp = fopen(git_path(commit_editmsg), "w");
 	if (fp == NULL)
-		die("could not open %s", git_path(commit_editmsg));
+		die("could not open %s: %s",
+		    git_path(commit_editmsg), strerror(errno));
 
 	if (cleanup_mode != CLEANUP_NONE)
 		stripspace(&sb, 0);