diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 2d3d88ea1879600643097a430dc5c5cf5bb00521..f6e4c3c33c07b82c526502b359d2274c484fc120 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -40,7 +40,8 @@ jobs:
         pip wheel --wheel-dir ./wheelhouse git+https://github.com/tahoe-lafs/tahoe-lafs@master#egg=tahoe-lafs
     - name: "Install Dependencies"
       run: |
-        PIP_FIND_LINKS=./wheelhouse python -m pip install ./
+        $Env:PIP_FIND_LINKS = "./wheelhouse"
+        python -m pip install ./
 
     - name: "Run Tests"
       env: