From f140e0031693b8243d496aa86bf62b66e9dd87ba Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 16 Dec 2015 10:35:33 +0530
Subject: [PATCH] ...

---
 src/calibre/utils/exim.py | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/calibre/utils/exim.py b/src/calibre/utils/exim.py
index d5b69c41d8..4759f9a4db 100644
--- a/src/calibre/utils/exim.py
+++ b/src/calibre/utils/exim.py
@@ -146,14 +146,12 @@ def all_known_libraries():
         paths.add(prefs['library_path'])
     added = set()
     for path in paths:
-        mdb = os.path.join(path)
-        if os.path.isdir(path) and os.path.exists(mdb):
-            seen = False
+        mdb = os.path.join(path, 'metadata.db')
+        if os.path.exists(mdb):
             for c in added:
-                if samefile(mdb, c):
-                    seen = True
+                if samefile(mdb, os.path.join(c, 'metadata.db')):
                     break
-            if not seen:
+            else:
                 added.add(path)
     return added