diff --git a/System/X509/MacOS.hs b/System/X509/MacOS.hs
--- a/System/X509/MacOS.hs
+++ b/System/X509/MacOS.hs
@@ -11,16 +11,19 @@
 import Data.X509
 import Data.X509.CertificateStore
 
-rootCAKeyChain :: String
+rootCAKeyChain :: FilePath
 rootCAKeyChain = "/System/Library/Keychains/SystemRootCertificates.keychain"
 
-listInKeyChain :: String -> IO [SignedCertificate]
-listInKeyChain keyChain = do
-    (_, Just hout, _, ph) <- createProcess (proc "security" ["find-certificate", "-pa", keyChain]) { std_out = CreatePipe }
+systemKeyChain :: FilePath
+systemKeyChain = "/Library/Keychains/System.keychain"
+
+listInKeyChains :: [FilePath] -> IO [SignedCertificate]
+listInKeyChains keyChains = do
+    (_, Just hout, _, ph) <- createProcess (proc "security" ("find-certificate" : "-pa" : keyChains)) { std_out = CreatePipe }
     pems <- either error id . pemParseLBS <$> LBS.hGetContents hout
     let targets = rights $ map (decodeSignedCertificate . pemContent) $ filter ((=="CERTIFICATE") . pemName) pems
     _ <- targets `seq` waitForProcess ph
     return targets
 
 getSystemCertificateStore :: IO CertificateStore
-getSystemCertificateStore = makeCertificateStore <$> listInKeyChain rootCAKeyChain
+getSystemCertificateStore = makeCertificateStore <$> listInKeyChains [rootCAKeyChain, systemKeyChain]
diff --git a/System/X509/Win32.hs b/System/X509/Win32.hs
--- a/System/X509/Win32.hs
+++ b/System/X509/Win32.hs
@@ -11,11 +11,13 @@
 
 import Control.Monad (when)
 import Control.Applicative
+import Control.Exception (catch)
 
 import qualified Data.ByteString.Internal as B
 
 import Data.X509
 import Data.X509.CertificateStore
+import Data.ASN1.Error
 
 import System.Win32.Types
 
@@ -64,4 +66,4 @@
                     case ecert of
                         Left _     -> loop st r
                         Right cert -> (cert :) <$> (loop st r)
-
+                    `catch` \(_ :: ASN1Error) -> loop st r
diff --git a/x509-system.cabal b/x509-system.cabal
--- a/x509-system.cabal
+++ b/x509-system.cabal
@@ -1,5 +1,5 @@
 Name:                x509-system
-Version:             1.6.0
+Version:             1.6.1
 Description:         System X.509 handling
 License:             BSD3
 License-file:        LICENSE
@@ -30,7 +30,7 @@
   ghc-options:       -Wall
   if os(windows)
      cpp-options:     -DWINDOWS
-     Build-Depends:   Win32
+     Build-Depends:   Win32, asn1-encoding
      extra-libraries: Crypt32
      Exposed-modules: System.X509.Win32
   if os(OSX)