diff --git a/dlls/ntdll/tests/virtual.c b/dlls/ntdll/tests/virtual.c
index 59c22248162..beab744178a 100644
--- a/dlls/ntdll/tests/virtual.c
+++ b/dlls/ntdll/tests/virtual.c
@@ -531,6 +531,9 @@ static void test_user_shared_data(void)
     ok(user_shared_data->ActiveProcessorCount == NtCurrentTeb()->Peb->NumberOfProcessors
             || broken(!user_shared_data->ActiveProcessorCount) /* before Win7 */,
             "Got unexpected ActiveProcessorCount %u.\n", user_shared_data->ActiveProcessorCount);
+    ok(user_shared_data->ActiveGroupCount == 1
+            || broken(!user_shared_data->ActiveGroupCount) /* before Win7 */,
+            "Got unexpected ActiveGroupCount %u.\n", user_shared_data->ActiveGroupCount);
 }
 
 START_TEST(virtual)
diff --git a/dlls/ntdll/thread.c b/dlls/ntdll/thread.c
index 78574d0c5d0..3d370f7a980 100644
--- a/dlls/ntdll/thread.c
+++ b/dlls/ntdll/thread.c
@@ -239,6 +239,7 @@ static void fill_user_shared_data( struct _KUSER_SHARED_DATA *data )
         break;
     }
     data->ActiveProcessorCount = NtCurrentTeb()->Peb->NumberOfProcessors;
+    data->ActiveGroupCount = 1;
 }
 
 HANDLE user_shared_data_init_done(void)