diff --git a/sidebar.c b/sidebar.c
index 5a9cfcb..58ba56d 100755
--- a/sidebar.c
+++ b/sidebar.c
@@ -759,8 +759,12 @@ draw_sidebar (int first_row, int num_rows, int div_width)
 		if (maildir_is_prefix && option (OPTSIDEBARFOLDERINDENT)) {
 			const char *tmp_folder_name;
 			int lastsep = 0;
+			size_t maxidx = 0;
 			tmp_folder_name = b->path + maildirlen + 1;
-			for (i = 0; i < strlen (tmp_folder_name) - 1; i++) {
+			if (tmp_folder_name[0]) {
+				maxidx = strlen(tmp_folder_name) - 1;
+			}
+			for (i = 0; i < maxidx; i++) {
 				if (SidebarDelimChars &&
 						strchr (SidebarDelimChars, tmp_folder_name[i])) {
 					sidebar_folder_depth++;