diff --git a/code/sys/sys_unix.c b/code/sys/sys_unix.c
index e0c63238..66b6fa17 100644
--- a/code/sys/sys_unix.c
+++ b/code/sys/sys_unix.c
@@ -346,6 +346,10 @@ void Sys_ListFilteredFiles( const char *basedir, char *subdirs, char *filter, ch
 		return;
 	}
 
+	if ( basedir[0] == '\0' ) {
+		return;
+	}
+
 	if (strlen(subdirs)) {
 		Com_sprintf( search, sizeof(search), "%s/%s", basedir, subdirs );
 	}
@@ -425,6 +429,11 @@ char **Sys_ListFiles( const char *directory, const char *extension, char *filter
 		return listCopy;
 	}
 
+	if ( directory[0] == '\0' ) {
+		*numfiles = 0;
+		return NULL;
+	}
+
 	if ( !extension)
 		extension = "";
 
diff --git a/code/sys/sys_win32.c b/code/sys/sys_win32.c
index e40caaa0..d5e1c637 100644
--- a/code/sys/sys_win32.c
+++ b/code/sys/sys_win32.c
@@ -483,6 +483,10 @@ void Sys_ListFilteredFiles( const char *basedir, char *subdirs, char *filter, ch
 		return;
 	}
 
+	if ( basedir[0] == '\0' ) {
+		return;
+	}
+
 	if (strlen(subdirs)) {
 		Com_sprintf( search, sizeof(search), "%s\\%s\\*", basedir, subdirs );
 	}
@@ -584,6 +588,11 @@ char **Sys_ListFiles( const char *directory, const char *extension, char *filter
 		return listCopy;
 	}
 
+	if ( directory[0] == '\0' ) {
+		*numfiles = 0;
+		return NULL;
+	}
+
 	if ( !extension) {
 		extension = "";
 	}