diff --git a/Sandboxie/core/drv/obj.h b/Sandboxie/core/drv/obj.h
index d4978dc6..176c3534 100644
--- a/Sandboxie/core/drv/obj.h
+++ b/Sandboxie/core/drv/obj.h
@@ -90,6 +90,7 @@ extern const OBJECT_NAME_INFORMATION Obj_Unnamed;
 extern P_ObGetObjectType pObGetObjectType;
 extern P_ObQueryNameInfo pObQueryNameInfo;
 
+extern BOOLEAN Obj_CallbackInstalled;
 
 //---------------------------------------------------------------------------
 // Macros Related to ParseProcedure
diff --git a/Sandboxie/core/drv/syscall_open.c b/Sandboxie/core/drv/syscall_open.c
index e149b61f..cd369486 100644
--- a/Sandboxie/core/drv/syscall_open.c
+++ b/Sandboxie/core/drv/syscall_open.c
@@ -435,7 +435,8 @@ _FX NTSTATUS Syscall_GetNextThread(
 
     if (NT_SUCCESS(status)) {
 
-        status = Thread_CheckObject_Common(proc, ProcessObject, DesiredAccess, FALSE);
+		ACCESS_MASK WriteAccess = (DesiredAccess & THREAD_DENIED_ACCESS_MASK);
+        status = Thread_CheckObject_Common(proc, ProcessObject, DesiredAccess, WriteAccess, L'T');
 
         ObDereferenceObject(ProcessObject);
     }