diff --git a/.travis.yml b/.travis.yml
index 7ca0fcf..d80c2e0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -25,6 +25,7 @@ install:
 script:
   - cabal configure --enable-tests
   - cabal build
+  - ghc-pkg unregister transformers
   - cabal test
   - cabal check
   - cabal sdist