diff --git a/kallithea/lib/utils.py b/kallithea/lib/utils.py
--- a/kallithea/lib/utils.py
+++ b/kallithea/lib/utils.py
@@ -36,6 +36,7 @@ from distutils.version import StrictVers
 
 import beaker.cache
 import mercurial.config
+import mercurial.error
 import mercurial.ui
 
 import kallithea.config.conf
@@ -235,6 +236,8 @@ def is_valid_repo_uri(repo_type, url, ui
                 MercurialRepository._check_url(url, ui)
             except urllib.error.URLError as e:
                 raise InvalidCloneUriException('URI %s URLError: %s' % (url, e))
+            except mercurial.error.RepoError as e:
+                raise InvalidCloneUriException('Mercurial %s: %s' % (type(e).__name__, safe_str(bytes(e))))
         elif url.startswith('svn+http'):
             try:
                 from hgsubversion.svnrepo import svnremoterepo