diff --git a/t/db_dependent/Auth.t b/t/db_dependent/Auth.t
index 8e4ea0bee9..d19efb7e3d 100644
--- a/t/db_dependent/Auth.t
+++ b/t/db_dependent/Auth.t
@@ -28,6 +28,10 @@ my $schema  = Koha::Database->schema;
 my $builder = t::lib::TestBuilder->new;
 my $dbh     = C4::Context->dbh;
 
+# FIXME: SessionStorage defaults to mysql, but it seems to break transaction
+# handling
+t::lib::Mocks::mock_preference( 'SessionStorage', 'tmp' );
+
 $schema->storage->txn_begin;
 
 subtest 'checkauth() tests' => sub {