diff --git a/LibGit2Sharp/Core/Handles/OidSafeHandle.cs b/LibGit2Sharp/Core/Handles/OidSafeHandle.cs
index a30959506..ced01e50a 100644
--- a/LibGit2Sharp/Core/Handles/OidSafeHandle.cs
+++ b/LibGit2Sharp/Core/Handles/OidSafeHandle.cs
@@ -7,7 +7,7 @@ internal class OidSafeHandle : NotOwnedSafeHandleBase
     {
         private GitOid? MarshalAsGitOid()
         {
-            return IsInvalid ? null : (GitOid?)MarshalAsGitOid(handle);
+            return IsZero || IsInvalid ? null : (GitOid?)MarshalAsGitOid(handle);
         }
 
         private static GitOid MarshalAsGitOid(IntPtr data)