diff --git a/src/sat/bsat/satProof.c b/src/sat/bsat/satProof.c
index d54f94b49..7613e0221 100644
--- a/src/sat/bsat/satProof.c
+++ b/src/sat/bsat/satProof.c
@@ -397,6 +397,8 @@ int Sat_ProofReduce( Vec_Set_t * vProof, void * pRoots, int hProofPivot )
     static clock_t TimeTotal = 0;
     int RetValue;
 
+Sat_ProofCheck0( vProof );
+
     // collect visited nodes
     nSize = Proof_MarkUsedRec( vProof, vRoots );
     vUsed = Vec_PtrAlloc( nSize );