diff --git a/wix/mackerel-agent.wxs b/wix/mackerel-agent.wxs
index d43a10269..b0e230050 100644
--- a/wix/mackerel-agent.wxs
+++ b/wix/mackerel-agent.wxs
@@ -44,6 +44,7 @@
 
     <InstallExecuteSequence>
       <Custom Action="FillApiKey" Before="StartServices">Not Installed</Custom>
+      <RemoveExistingProducts Before="InstallInitialize" />
     </InstallExecuteSequence>
 
   </Product>