diff --git a/src/calibre/ebooks/mobi/reader.py b/src/calibre/ebooks/mobi/reader.py
index a37285a47c..d3a154e32d 100644
--- a/src/calibre/ebooks/mobi/reader.py
+++ b/src/calibre/ebooks/mobi/reader.py
@@ -489,6 +489,9 @@ class MobiReader(object):
         mobi_version = self.book_header.mobi_version
         for i, tag in enumerate(root.iter(etree.Element)):
             tag.attrib.pop('xmlns', '')
+            for x in tag.attrib:
+                if ':' in x:
+                    del tag.attrib[x]
             if tag.tag in ('country-region', 'place', 'placetype', 'placename',
                 'state', 'city', 'street', 'address', 'content'):
                 tag.tag = 'div' if tag.tag == 'content' else 'span'
diff --git a/src/calibre/linux.py b/src/calibre/linux.py
index c0e76b8690..d22cbf7cbd 100644
--- a/src/calibre/linux.py
+++ b/src/calibre/linux.py
@@ -140,8 +140,8 @@ class PostInstall:
             for f in os.listdir('.'):
                 if os.stat(f).st_uid == 0:
                     os.rmdir(f) if os.path.isdir(f) else os.unlink(f)
-        if os.stat(config_dir).st_uid == 0:
-            os.rmdir(config_dir)
+            if os.stat(config_dir).st_uid == 0:
+                os.rmdir(config_dir)
 
         if warn is None and self.warnings:
             self.info('There were %d warnings'%len(self.warnings))