diff --git a/Source/BPBIOS/Clean.cmd b/Source/BPBIOS/Clean.cmd
index 5bcf9d9e..f713819a 100644
--- a/Source/BPBIOS/Clean.cmd
+++ b/Source/BPBIOS/Clean.cmd
@@ -8,6 +8,7 @@ if exist *.img del *.img
 if exist bp*.rel del bp*.rel
 if exist zcpr33*.rel del zcpr33*.rel
 if exist *.bak del *.bak
+if exist def-ww.lib del def-ww.lib
 
 setlocal & cd ZCPR33 && call Clean.cmd & endlocal
 setlocal & cd Z34RCP11 && call Clean.cmd & endlocal