diff --git a/appveyor.yml b/appveyor.yml
index b33418e05..2fa4b2dd2 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -29,6 +29,14 @@ install:
     $ProgressPreference = 'SilentlyContinue'
 
 
+    git submodule sync
+
+
+    if ($LastExitCode -ne 0) {
+        throw "Last command failed."
+    }
+
+
     git submodule update --init --recursive
 
 
@@ -36,6 +44,7 @@ install:
         throw "Last command failed."
     }
 
+
     if ($env:DOTNET_CHANNEL) {
         dotnet --info