diff --git a/HISTORY.md b/HISTORY.md
index d167f71..4fb30be 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,7 +1,7 @@
 ## History of versions ##
 
-* version 4.2 (2015-08-30)
-  * Now can work with old and new versions of AVConv
+#* version 4.2 (2015-08-30)
+#  * Now can work with old and new versions of AVConv
 
 * version 4.1 (2015-06-30)
   * Fixed dependencies in package
diff --git a/src/devedeng/avbase.py b/src/devedeng/avbase.py
index b22603d..1d4e49a 100644
--- a/src/devedeng/avbase.py
+++ b/src/devedeng/avbase.py
@@ -40,6 +40,8 @@ class avbase(devedeng.executor.executor):
         self.minor_version = 0
        
         for line in vtext:
+            if not isinstance(line, str):
+                continue
             if (line.startswith("avconv version")):
                 pos1 = line.find('.',15)
                 pos2 = line.find('-',15)