diff --git a/conda-envs/environment-test.yml b/conda-envs/environment-test.yml
index b950de8e..6c57d5ae 100644
--- a/conda-envs/environment-test.yml
+++ b/conda-envs/environment-test.yml
@@ -1,7 +1,7 @@
 name: pymc-experimental-test
 channels:
 - conda-forge
-- defaults
+- nodefaults
 dependencies:
 - pip
 - pymc>=5.1.2
diff --git a/conda-envs/windows-environment-test.yml b/conda-envs/windows-environment-test.yml
index e419eb4a..0a5d813a 100644
--- a/conda-envs/windows-environment-test.yml
+++ b/conda-envs/windows-environment-test.yml
@@ -1,7 +1,7 @@
 name: pymc-experimental-test
 channels:
 - conda-forge
-- defaults
+- nodefaults
 dependencies:
 - pip
 - pymc>=5.1.2