diff --git a/src/calibre/__init__.py b/src/calibre/__init__.py
index 989ad3de84..2ed2173d87 100644
--- a/src/calibre/__init__.py
+++ b/src/calibre/__init__.py
@@ -527,7 +527,7 @@ def entity_to_unicode(match, exceptions=[], encoding='cp1252',
     ent = match.group(1)
     if ent in exceptions:
         return '&'+ent+';'
-    if ent == 'apos':
+    if ent in {'apos', 'squot'}: # squot is generated by some broken CMS software
         return check("'")
     if ent == 'hellips':
         ent = 'hellip'