diff --git a/offlineimap/repository/IMAP.py b/offlineimap/repository/IMAP.py
index a6c330e..68f1800 100644
--- a/offlineimap/repository/IMAP.py
+++ b/offlineimap/repository/IMAP.py
@@ -233,13 +233,15 @@ class IMAPRepository(BaseRepository):
     def getsslcacertfile(self):
         """Determines CA bundle.
 
-        Returns path to the CA bundle.  It is either explicitely specified
-        or requested via "OS-DEFAULT" value (and we will search known
-        locations for the current OS and distribution).
+        Returns path to the CA bundle.  It is explicitely specified or
+        requested via "OS-DEFAULT" value (and we will search known
+        locations for the current OS and distribution). If it is not
+        specified, we will search it in the known locations.
 
-        If search via "OS-DEFAULT" route yields nothing, we will throw an
-        exception to make our callers distinguish between not specified
-        value and non-existent default CA bundle.
+        If search route, via "OS-DEFAULT" or because is not specified,
+        yields nothing, we will throw an exception to make our callers
+        distinguish between not specified value and non-existent
+        default CA bundle.
 
         It is also an error to specify non-existent file via configuration:
         it will error out later, but, perhaps, with less verbose explanation,
@@ -250,7 +252,10 @@ class IMAPRepository(BaseRepository):
         xforms = [os.path.expanduser, os.path.expandvars, os.path.abspath]
         cacertfile = self.getconf_xform('sslcacertfile', xforms, None)
         # Can't use above cacertfile because of abspath.
-        if self.getconf('sslcacertfile', None) == "OS-DEFAULT":
+        conf_sslacertfile = self.getconf('sslcacertfile', None)
+        if conf_sslacertfile == "OS-DEFAULT" or \
+            conf_sslacertfile == None or \
+            conf_sslacertfile == '':
             cacertfile = get_os_sslcertfile()
             if cacertfile is None:
                 searchpath = get_os_sslcertfile_searchpath()