diff --git a/thys/GewirthPGCProof/ROOT b/thys/GewirthPGCProof/ROOT
--- a/thys/GewirthPGCProof/ROOT
+++ b/thys/GewirthPGCProof/ROOT
@@ -1,12 +1,12 @@
 chapter AFP
 
 session GewirthPGCProof (AFP) = HOL +
-  options [timeout = 300]
+  options [timeout = 300, kodkod_scala = false]
 
   theories
     CJDDLplus
 	ExtendedDDL
 	GewirthArgument
   document_files
     "root.tex"
     "root.bib"