diff --git a/src/calibre/ebooks/conversion/preprocess.py b/src/calibre/ebooks/conversion/preprocess.py
index fb55ee74fb..42e6654127 100644
--- a/src/calibre/ebooks/conversion/preprocess.py
+++ b/src/calibre/ebooks/conversion/preprocess.py
@@ -26,9 +26,9 @@ def sanitize_head(match):
 def chap_head(match):
     chap = match.group('chap')
     title = match.group('title')
-    if not title: 
+    if not title:
                return '<h1>'+chap+'</h1><br/>'
-    else: 
+    else:
                return '<h1>'+chap+'<br/>'+title+'</h1><br/>'
 
 
@@ -49,19 +49,19 @@ def line_length(raw, percent):
     total = sum(lengths)
     avg = total / len(lengths)
     max_line = avg * 2
-    
+
     lengths = sorted(lengths)
     for i in range(len(lengths) - 1, -1, -1):
         if lengths[i] > max_line:
             del lengths[i]
-    
+
     if percent > 1:
         percent = 1
     if percent < 0:
         percent = 0
 
     index = int(len(lengths) * percent) - 1
-    
+
     return lengths[index]
 
 
@@ -110,17 +110,17 @@ class HTMLPreProcessor(object):
 
                   # Remove non breaking spaces
                   (re.compile(ur'\u00a0'), lambda match : ' '),
-                  
+
                   # Detect Chapters to match default XPATH in GUI
                   (re.compile(r'(<br[^>]*>)?(</?p[^>]*>)?s*(?P<chap>(Chapter|Epilogue|Prologue|Book|Part)\s*(\d+|\w+)?)(</?p[^>]*>|<br[^>]*>)\n?((?=(<i>)?\s*\w+(\s+\w+)?(</i>)?(<br[^>]*>|</?p[^>]*>))((?P<title>.*)(<br[^>]*>|</?p[^>]*>)))?', re.IGNORECASE), chap_head),
                   (re.compile(r'(<br[^>]*>)?(</?p[^>]*>)?s*(?P<chap>([A-Z \'"!]{5,})\s*(\d+|\w+)?)(</?p[^>]*>|<br[^>]*>)\n?((?=(<i>)?\s*\w+(\s+\w+)?(</i>)?(<br[^>]*>|</?p[^>]*>))((?P<title>.*)(<br[^>]*>|</?p[^>]*>)))?'), chap_head),
- 
+
                   # Have paragraphs show better
                   (re.compile(r'<br.*?>'), lambda match : '<p>'),
-                  
+
                   # Un wrap lines
                   (re.compile(r'(?<=[^\.^\^?^!^"^”])\s*(</(i|b|u)>)*\s*<p.*?>\s*(<(i|b|u)>)*\s*(?=[a-z0-9I])', re.UNICODE), lambda match: ' '),
-                  
+
                   # Clean up spaces
                   (re.compile(u'(?<=[\.,:;\?!”"\'])[\s^ ]*(?=<)'), lambda match: ' '),
                   # Add space before and after italics
@@ -157,6 +157,7 @@ class HTMLPreProcessor(object):
     def __call__(self, html, remove_special_chars=None):
         if remove_special_chars is not None:
             html = remove_special_chars.sub('', html)
+        html = html.replace('\0', '')
         if self.is_baen(html):
             rules = []
         elif self.is_book_designer(html):
@@ -166,7 +167,7 @@ class HTMLPreProcessor(object):
             #line_length_rules = [
             #    (re.compile('%i' % line_length(html, .85)), lambda match:)
             #]
-            
+
             rules = self.PDFTOHTML # + line_length_rules
         else:
             rules = []