diff --git a/programs/fileio.c b/programs/fileio.c
index 2a7d73d1..c0ec891e 100644
--- a/programs/fileio.c
+++ b/programs/fileio.c
@@ -433,6 +433,10 @@ static int FIO_compressFilename_extRess(cRess_t ress,
 
     result = FIO_compressFilename_internal(ress, dstFileName, srcFileName, cLevel);
 
+    if (result != 0) {
+      remove(dstFileName);
+    }
+
     fclose(ress.srcFile);   /* no pb to expect : only reading */
     if (fclose(ress.dstFile)) EXM_THROW(28, "Write error : cannot properly close %s", dstFileName);
     return result;
@@ -638,13 +642,17 @@ static int FIO_decompressSrcFile(dRess_t ress, const char* srcFileName)
 static int FIO_decompressFile_extRess(dRess_t ress,
                                       const char* dstFileName, const char* srcFileName)
 {
+    int result;
     ress.dstFile = FIO_openDstFile(dstFileName);
     if (ress.dstFile==0) return 1;
 
-    FIO_decompressSrcFile(ress, srcFileName);
+    result = FIO_decompressSrcFile(ress, srcFileName);
+    if (result != 0) {
+      remove(dstFileName);
+    }
 
     if (fclose(ress.dstFile)) EXM_THROW(38, "Write error : cannot properly close %s", dstFileName);
-    return 0;
+    return result;
 }
 
 
diff --git a/programs/playTests.sh b/programs/playTests.sh
index ec625ee8..891ab9d4 100755
--- a/programs/playTests.sh
+++ b/programs/playTests.sh
@@ -36,7 +36,10 @@ $ZSTD --decompress tmpCompressed --stdout > tmpResult
 $ZSTD -q tmp && die "overwrite check failed!"
 $ZSTD -q -f tmp
 $ZSTD -q --force tmp
-
+$ZSTD -df tmp && die "should have refused : wrong extension"
+cp tmp tmp2.zst
+$ZSTD -df tmp2.zst && die "should have failed : wrong format"
+rm tmp2.zst
 
 echo "\n**** frame concatenation **** "