diff --git a/src/base/abci/abc.c b/src/base/abci/abc.c
index 9bd21963b..066af958a 100644
--- a/src/base/abci/abc.c
+++ b/src/base/abci/abc.c
@@ -30247,7 +30247,7 @@ int Abc_CommandPdr( Abc_Frame_t * pAbc, int argc, char ** argv )
     int c;
     Pdr_ManSetDefaultParams( pPars );
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "MFCDQTHGSLIXaxrmuyfqipdegjonctkvwzh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "MFCDQTHGSLIaxrmuyfqipdegjonctkvwzh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -30368,15 +30368,6 @@ int Abc_CommandPdr( Abc_Frame_t * pAbc, int argc, char ** argv )
             pPars->pInvFileName = argv[globalUtilOptind];
             globalUtilOptind++;
             break;
-        case 'X':
-            if ( globalUtilOptind >= argc )
-            {
-                Abc_Print( -1, "Command line switch \"-X\" should be followed by a directory name.\n" );
-                goto usage;
-            }
-            pPars->pCexFilePrefix = argv[globalUtilOptind];
-            globalUtilOptind++;
-            break;
         case 'a':
             pPars->fSolveAll ^= 1;
             break;
@@ -30484,7 +30475,7 @@ int Abc_CommandPdr( Abc_Frame_t * pAbc, int argc, char ** argv )
     return 0;
 
 usage:
-    Abc_Print( -2, "usage: pdr [-MFCDQTHGS <num>] [-LI <file>] [-X <prefix>] [-axrmuyfqipdegjonctkvwzh]\n" );
+    Abc_Print( -2, "usage: pdr [-MFCDQTHGS <num>] [-LI <file>] [-axrmuyfqipdegjonctkvwzh]\n" );
     Abc_Print( -2, "\t         model checking using property directed reachability (aka IC3)\n" );
     Abc_Print( -2, "\t         pioneered by Aaron R. Bradley (http://theory.stanford.edu/~arbrad/)\n" );
     Abc_Print( -2, "\t         with improvements by Niklas Een (http://een.se/niklas/)\n" );
@@ -30499,7 +30490,6 @@ int Abc_CommandPdr( Abc_Frame_t * pAbc, int argc, char ** argv )
     Abc_Print( -2, "\t-S num : * value to seed the SAT solver with [default = %d]\n",                          pPars->nRandomSeed );
     Abc_Print( -2, "\t-L file: the log file name [default = %s]\n",                                          pLogFileName ? pLogFileName : "no logging" );
     Abc_Print( -2, "\t-I file: the invariant file name [default = %s]\n",                                    pPars->pInvFileName ? pPars->pInvFileName : "default name" );
-    Abc_Print( -2, "\t-X pref: when solving all outputs, store CEXes immediately as <pref>*.aiw [default = %s]\n", pPars->pCexFilePrefix ? pPars->pCexFilePrefix : "disabled");
     Abc_Print( -2, "\t-a     : toggle solving all outputs even if one of them is SAT [default = %s]\n",      pPars->fSolveAll? "yes": "no" );
     Abc_Print( -2, "\t-x     : toggle storing CEXes when solving all outputs [default = %s]\n",              pPars->fStoreCex? "yes": "no" );
     Abc_Print( -2, "\t-r     : toggle using more effort in generalization [default = %s]\n",                 pPars->fTwoRounds? "yes": "no" );
diff --git a/src/proof/pdr/pdr.h b/src/proof/pdr/pdr.h
index 00d15a8bc..d8a548d5c 100644
--- a/src/proof/pdr/pdr.h
+++ b/src/proof/pdr/pdr.h
@@ -84,7 +84,6 @@ struct Pdr_Par_t_
     abctime timeLastSolved; // the time when the last output was solved
     Vec_Int_t * vOutMap;  // in the multi-output mode, contains status for each PO (0 = sat; 1 = unsat; negative = undecided)
     char * pInvFileName;  // invariable file name
-    char * pCexFilePrefix;  // CEX output prefix
 };
 
 ////////////////////////////////////////////////////////////////////////
@@ -96,7 +95,6 @@ struct Pdr_Par_t_
 ////////////////////////////////////////////////////////////////////////
 
 /*=== pdrCore.c ==========================================================*/
-extern void               Pdr_OutputCexToDir( Pdr_Par_t * pPars, Abc_Cex_t * pCex );
 extern void               Pdr_ManSetDefaultParams( Pdr_Par_t * pPars );
 extern int                Pdr_ManSolve( Aig_Man_t * p, Pdr_Par_t * pPars );
 
diff --git a/src/proof/pdr/pdrCore.c b/src/proof/pdr/pdrCore.c
index 371dda168..34a327034 100644
--- a/src/proof/pdr/pdrCore.c
+++ b/src/proof/pdr/pdrCore.c
@@ -80,7 +80,6 @@ void Pdr_ManSetDefaultParams( Pdr_Par_t * pPars )
     pPars->nDropOuts      =       0;  // the number of timed out outputs
     pPars->timeLastSolved =       0;  // last one solved
     pPars->pInvFileName   =    NULL;  // invariant file name
-    pPars->pCexFilePrefix =    NULL;  // CEX output prefix
 }
 
 /**Function*************************************************************
@@ -1027,38 +1026,6 @@ int Pdr_ManBlockCube( Pdr_Man_t * p, Pdr_Set_t * pCube )
     return 1;
 }
 
-void Pdr_OutputCexToDir( Pdr_Par_t * pPars, Abc_Cex_t * pCex )
-{
-    int i, f, iBit;
-    size_t iCexPathSize;
-    char * pCexPath;
-    FILE * pCexFile;
-
-    iCexPathSize = snprintf( NULL, 0, "%s%d.aiw", pPars->pCexFilePrefix, pCex->iPo ) + 1;
-    pCexPath = malloc( iCexPathSize );
-    snprintf( pCexPath, iCexPathSize, "%s%d.aiw", pPars->pCexFilePrefix, pCex->iPo );
-    Abc_Print( 1, "Writing CEX for output %d to %s\n", pCex->iPo, pCexPath );
-    pCexFile = fopen( pCexPath, "w" );
-    free( pCexPath );
-
-    fprintf( pCexFile, "1\n");
-    fprintf( pCexFile, "b%d\n", pCex->iPo);
-
-    iBit = 0;
-    for ( i = 0; i < pCex->nRegs; i++, iBit++ )
-        putc( '0' + Abc_InfoHasBit(pCex->pData, iBit), pCexFile );
-    putc( '\n', pCexFile );
-
-    for ( f = 0; f <= pCex->iFrame; f++ )
-    {
-        for ( i = 0; i < pCex->nPis; i++, iBit++ )
-            putc( '0' + Abc_InfoHasBit(pCex->pData, iBit), pCexFile );
-        putc( '\n', pCexFile );
-    }
-    fprintf( pCexFile, ".\n");
-    fclose( pCexFile );
-}
-
 /**Function*************************************************************
 
   Synopsis    []
@@ -1133,7 +1100,7 @@ int Pdr_ManSolveInt( Pdr_Man_t * p )
                     p->pAig->pSeqModel = pCexNew;
                     return 0; // SAT
                 }
-                pCexNew = (p->pPars->fUseBridge || p->pPars->fStoreCex || p->pPars->pCexFilePrefix) ? Abc_CexMakeTriv( Aig_ManRegNum(p->pAig), Saig_ManPiNum(p->pAig), Saig_ManPoNum(p->pAig), iFrame*Saig_ManPoNum(p->pAig)+p->iOutCur ) : (Abc_Cex_t *)(ABC_PTRINT_T)1;
+                pCexNew = (p->pPars->fUseBridge || p->pPars->fStoreCex) ? Abc_CexMakeTriv( Aig_ManRegNum(p->pAig), Saig_ManPiNum(p->pAig), Saig_ManPoNum(p->pAig), iFrame*Saig_ManPoNum(p->pAig)+p->iOutCur ) : (Abc_Cex_t *)(ABC_PTRINT_T)1;
                 p->pPars->nFailOuts++;
                 if ( p->pPars->vOutMap ) Vec_IntWriteEntry( p->pPars->vOutMap, p->iOutCur, 0 );
                 if ( !p->pPars->fNotVerbose )
@@ -1142,8 +1109,6 @@ int Pdr_ManSolveInt( Pdr_Man_t * p )
                 assert( Vec_PtrEntry(p->vCexes, p->iOutCur) == NULL );
                 if ( p->pPars->fUseBridge )
                     Gia_ManToBridgeResult( stdout, 0, pCexNew, pCexNew->iPo );
-                if ( p->pPars->pCexFilePrefix )
-                    Pdr_OutputCexToDir( p->pPars, pCexNew );
                 Vec_PtrWriteEntry( p->vCexes, p->iOutCur, pCexNew );
                 if ( p->pPars->pFuncOnFail && p->pPars->pFuncOnFail(p->iOutCur, p->pPars->fStoreCex ? (Abc_Cex_t *)Vec_PtrEntry(p->vCexes, p->iOutCur) : NULL) )
                 {
@@ -1252,13 +1217,11 @@ int Pdr_ManSolveInt( Pdr_Man_t * p )
                             return 0; // SAT
                         }
                         p->pPars->nFailOuts++;
-                        pCexNew = (p->pPars->fUseBridge || p->pPars->fStoreCex || p->pPars->pCexFilePrefix) ? Pdr_ManDeriveCex(p) : (Abc_Cex_t *)(ABC_PTRINT_T)1;
+                        pCexNew = (p->pPars->fUseBridge || p->pPars->fStoreCex) ? Pdr_ManDeriveCex(p) : (Abc_Cex_t *)(ABC_PTRINT_T)1;
                         if ( p->pPars->vOutMap ) Vec_IntWriteEntry( p->pPars->vOutMap, p->iOutCur, 0 );
                         assert( Vec_PtrEntry(p->vCexes, p->iOutCur) == NULL );
                         if ( p->pPars->fUseBridge )
                             Gia_ManToBridgeResult( stdout, 0, pCexNew, pCexNew->iPo );
-                        if ( p->pPars->pCexFilePrefix )
-                            Pdr_OutputCexToDir( p->pPars, pCexNew );
                         Vec_PtrWriteEntry( p->vCexes, p->iOutCur, pCexNew );
                         if ( p->pPars->pFuncOnFail && p->pPars->pFuncOnFail(p->iOutCur, p->pPars->fStoreCex ? (Abc_Cex_t *)Vec_PtrEntry(p->vCexes, p->iOutCur) : NULL) )
                         {
diff --git a/src/proof/pdr/pdrIncr.c b/src/proof/pdr/pdrIncr.c
index 6ba68db99..9ca72ba69 100644
--- a/src/proof/pdr/pdrIncr.c
+++ b/src/proof/pdr/pdrIncr.c
@@ -484,7 +484,7 @@ int IPdr_ManSolveInt( Pdr_Man_t * p, int fCheckClauses, int fPushClauses )
                     p->pAig->pSeqModel = pCexNew;
                     return 0; // SAT
                 }
-                pCexNew = (p->pPars->fUseBridge || p->pPars->fStoreCex || p->pPars->pCexFilePrefix) ? Abc_CexMakeTriv( Aig_ManRegNum(p->pAig), Saig_ManPiNum(p->pAig), Saig_ManPoNum(p->pAig), iFrame*Saig_ManPoNum(p->pAig)+p->iOutCur ) : (Abc_Cex_t *)(ABC_PTRINT_T)1;
+                pCexNew = (p->pPars->fUseBridge || p->pPars->fStoreCex) ? Abc_CexMakeTriv( Aig_ManRegNum(p->pAig), Saig_ManPiNum(p->pAig), Saig_ManPoNum(p->pAig), iFrame*Saig_ManPoNum(p->pAig)+p->iOutCur ) : (Abc_Cex_t *)(ABC_PTRINT_T)1;
                 p->pPars->nFailOuts++;
                 if ( p->pPars->vOutMap ) Vec_IntWriteEntry( p->pPars->vOutMap, p->iOutCur, 0 );
                 if ( !p->pPars->fNotVerbose )
@@ -493,8 +493,6 @@ int IPdr_ManSolveInt( Pdr_Man_t * p, int fCheckClauses, int fPushClauses )
                 assert( Vec_PtrEntry(p->vCexes, p->iOutCur) == NULL );
                 if ( p->pPars->fUseBridge )
                     Gia_ManToBridgeResult( stdout, 0, pCexNew, pCexNew->iPo );
-                if ( p->pPars->pCexFilePrefix )
-                    Pdr_OutputCexToDir( p->pPars, pCexNew );
                 Vec_PtrWriteEntry( p->vCexes, p->iOutCur, pCexNew );
                 if ( p->pPars->pFuncOnFail && p->pPars->pFuncOnFail(p->iOutCur, p->pPars->fStoreCex ? (Abc_Cex_t *)Vec_PtrEntry(p->vCexes, p->iOutCur) : NULL) )
                 {