diff --git a/src/filesystem.cpp b/src/filesystem.cpp
index fe5d403..71a0043 100644
--- a/src/filesystem.cpp
+++ b/src/filesystem.cpp
@@ -650,7 +650,8 @@ void FileSystem::openReadRaw(SDL_RWops &ops,
                              bool freeOnClose)
 {
 	PHYSFS_File *handle = PHYSFS_openRead(filename);
-	assert(handle);
+	if (!handle)
+		throw Exception(Exception::NoFileError, "%s", filename);
 
 	initReadOps(handle, ops, freeOnClose);
 }