diff --git a/GVFS/GVFS.Common/Git/GitProcess.cs b/GVFS/GVFS.Common/Git/GitProcess.cs
index 616d0ec22..a86b6131a 100644
--- a/GVFS/GVFS.Common/Git/GitProcess.cs
+++ b/GVFS/GVFS.Common/Git/GitProcess.cs
@@ -684,7 +684,7 @@ public Result MultiPackIndexRepack(string gitObjectDirectory, string batchSize)
 
         public Result GetHeadTreeId()
         {
-            return this.InvokeGitAgainstDotGitFolder("show -s --format=%T HEAD", usePreCommandHook: false);
+            return this.InvokeGitAgainstDotGitFolder("rev-parse \"HEAD^{tree}\"", usePreCommandHook: false);
         }
 
         public Process GetGitProcess(string command, string workingDirectory, string dotGitDirectory, bool useReadObjectHook, bool redirectStandardError, string gitObjectsDirectory, bool usePreCommandHook)
diff --git a/GVFS/GVFS.UnitTests/Common/EnlistmentHydrationSummaryTests.cs b/GVFS/GVFS.UnitTests/Common/EnlistmentHydrationSummaryTests.cs
index 53591de8a..2623dc4bd 100644
--- a/GVFS/GVFS.UnitTests/Common/EnlistmentHydrationSummaryTests.cs
+++ b/GVFS/GVFS.UnitTests/Common/EnlistmentHydrationSummaryTests.cs
@@ -100,7 +100,7 @@ public void HeadTreeCountCacheTests((string CachePrecontents, string ExpectedCac
                 this.enlistmentDirectory.CreateFile(totalPathCountPath, args.CachePrecontents, createDirectories: true);
             }
 
-            this.gitProcess.SetExpectedCommandResult("show -s --format=%T HEAD",
+            this.gitProcess.SetExpectedCommandResult("rev-parse \"HEAD^{tree}\"",
                 () => new GitProcess.Result(HeadTreeId, "", 0));
             this.gitProcess.SetExpectedCommandResult("ls-tree -r -d HEAD",
                 () => new GitProcess.Result(