diff --git a/.appveyor.yml b/.appveyor.yml
index afb0bcb6975..5352e9c73d1 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -13,7 +13,7 @@ environment:
   TEST_OPTIONS:
   DEPLOY: YES
   matrix:
-  - PYTHON: C:/Python38rc1-x64
+  - PYTHON: C:\Python38rc1-x64
   - PYTHON: C:/Python37
   - PYTHON: C:/Python37-x64
   - PYTHON: C:/Python36