diff --git a/appveyor.yml b/appveyor.yml
index c226253ac9c5f9d5ca56be4044b0d43460ba39e2..ad091115a9002a4b2559a563cdb01681c284b9c2 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -58,7 +58,7 @@ install:
 
     # Development installation
     - cmd: conda install --yes nose coverage
-    - cmd: pip install -y coveralls
+    - cmd: pip install coveralls
 
 # Skip .NET project specific build phase.
 build: off