diff --git a/src/calibre/ebooks/docx/styles.py b/src/calibre/ebooks/docx/styles.py
index 43b694b692..fbc5b9c13a 100644
--- a/src/calibre/ebooks/docx/styles.py
+++ b/src/calibre/ebooks/docx/styles.py
@@ -138,32 +138,32 @@ class Styles(object):
 
     def __call__(self, root, fonts, theme):
         self.fonts, self.theme = fonts, theme
-        for s in self.namespace.XPath('//w:style')(root):
-            s = Style(self.namespace, s)
-            if s.style_id:
-                self.id_map[s.style_id] = s
-            if s.is_default:
-                self.default_styles[s.style_type] = s
-            if getattr(s, 'numbering_style_link', None) is not None:
-                self.numbering_style_links[s.style_id] = s.numbering_style_link
-
         self.default_paragraph_style = self.default_character_style = None
+        if root is not None:
+            for s in self.namespace.XPath('//w:style')(root):
+                s = Style(self.namespace, s)
+                if s.style_id:
+                    self.id_map[s.style_id] = s
+                if s.is_default:
+                    self.default_styles[s.style_type] = s
+                if getattr(s, 'numbering_style_link', None) is not None:
+                    self.numbering_style_links[s.style_id] = s.numbering_style_link
 
-        for dd in self.namespace.XPath('./w:docDefaults')(root):
-            for pd in self.namespace.XPath('./w:pPrDefault')(dd):
-                for pPr in self.namespace.XPath('./w:pPr')(pd):
-                    ps = ParagraphStyle(self.namespace, pPr)
-                    if self.default_paragraph_style is None:
-                        self.default_paragraph_style = ps
-                    else:
-                        self.default_paragraph_style.update(ps)
-            for pd in self.namespace.XPath('./w:rPrDefault')(dd):
-                for pPr in self.namespace.XPath('./w:rPr')(pd):
-                    ps = RunStyle(self.namespace, pPr)
-                    if self.default_character_style is None:
-                        self.default_character_style = ps
-                    else:
-                        self.default_character_style.update(ps)
+            for dd in self.namespace.XPath('./w:docDefaults')(root):
+                for pd in self.namespace.XPath('./w:pPrDefault')(dd):
+                    for pPr in self.namespace.XPath('./w:pPr')(pd):
+                        ps = ParagraphStyle(self.namespace, pPr)
+                        if self.default_paragraph_style is None:
+                            self.default_paragraph_style = ps
+                        else:
+                            self.default_paragraph_style.update(ps)
+                for pd in self.namespace.XPath('./w:rPrDefault')(dd):
+                    for pPr in self.namespace.XPath('./w:rPr')(pd):
+                        ps = RunStyle(self.namespace, pPr)
+                        if self.default_character_style is None:
+                            self.default_character_style = ps
+                        else:
+                            self.default_character_style.update(ps)
 
         def resolve(s, p):
             if p is not None:
diff --git a/src/calibre/ebooks/docx/to_html.py b/src/calibre/ebooks/docx/to_html.py
index 21f2ac2281..8fd8c48d9e 100644
--- a/src/calibre/ebooks/docx/to_html.py
+++ b/src/calibre/ebooks/docx/to_html.py
@@ -331,6 +331,7 @@ class Convert(object):
             else:
                 self.theme(fromstring(raw))
 
+        styles_loaded = False
         if sname is not None:
             try:
                 raw = self.docx.read(sname)
@@ -338,6 +339,9 @@ class Convert(object):
                 self.log.warn('Styles %s do not exist' % sname)
             else:
                 self.styles(fromstring(raw), fonts, self.theme)
+                styles_loaded = True
+        if not styles_loaded:
+            self.styles(None, fonts, self.theme)
 
         if nname is not None:
             try: