diff --git a/cmdline/elem.c b/cmdline/elem.c
index 304b1f00..7cb270ba 100644
--- a/cmdline/elem.c
+++ b/cmdline/elem.c
@@ -84,7 +84,7 @@ struct snapraid_filter* filter_alloc_file(int direction, const char* pattern)
 			filter->is_dir = 0;
 		}
 
-		/* a slash must be the first char, as we reject PATH/DIR/FILE */
+		/* a slash must be the first char, as we don't support PATH/FILE and PATH/DIR/ */
 		if (filter->pattern[0] != '/') {
 			/* LCOV_EXCL_START */
 			free(filter);
diff --git a/cmdline/snapraid.c b/cmdline/snapraid.c
index 9d935812..9d06b3af 100644
--- a/cmdline/snapraid.c
+++ b/cmdline/snapraid.c
@@ -468,6 +468,7 @@ int main(int argc, char* argv[])
 			if (!filter) {
 				/* LCOV_EXCL_START */
 				log_fatal("Invalid filter specification '%s'\n", optarg);
+				log_fatal("Filters using relative paths are not supported. Ensure to add an initial slash\n");
 				exit(EXIT_FAILURE);
 				/* LCOV_EXCL_STOP */
 			}
diff --git a/cmdline/state.c b/cmdline/state.c
index 58c39741..f0b19a8e 100644
--- a/cmdline/state.c
+++ b/cmdline/state.c
@@ -886,6 +886,7 @@ void state_config(struct snapraid_state* state, const char* path, const char* co
 			if (!filter) {
 				/* LCOV_EXCL_START */
 				log_fatal("Invalid 'exclude' specification '%s' in '%s' at line %u\n", buffer, path, line);
+				log_fatal("Filters using relative paths are not supported. Ensure to add an initial slash\n");
 				exit(EXIT_FAILURE);
 				/* LCOV_EXCL_STOP */
 			}
@@ -912,6 +913,7 @@ void state_config(struct snapraid_state* state, const char* path, const char* co
 			if (!filter) {
 				/* LCOV_EXCL_START */
 				log_fatal("Invalid 'include' specification '%s' in '%s' at line %u\n", buffer, path, line);
+				log_fatal("Filters using relative paths are not supported. Ensure to add an initial slash\n");
 				exit(EXIT_FAILURE);
 				/* LCOV_EXCL_STOP */
 			}