diff --git a/scripts/target/mame/mess.lua b/scripts/target/mame/mess.lua
index 44fc11c12ca..633ab9e032e 100644
--- a/scripts/target/mame/mess.lua
+++ b/scripts/target/mame/mess.lua
@@ -1062,6 +1062,7 @@ FORMATS["CD90_640_DSK"] = true
 FORMATS["CGENIE_DSK"] = true
 FORMATS["CGEN_CAS"] = true
 FORMATS["COCO_CAS"] = true
+FORMATS["COCO_RAWDSK"] = true
 FORMATS["COMX35_DSK"] = true
 FORMATS["CONCEPT_DSK"] = true
 FORMATS["COUPEDSK"] = true