title: VSTO - Excel - How to call range.Validation.Delete() without raising an error?
body: <p>When I press <kbd>Alt</kbd> + <kbd>Down</kbd> keys before calling <code>range.Validation.Delete()</code>, Excel shows the following error:</p>
  <blockquote>
  <p>An exception of type 'System.Runtime.InteropServices.COMException' occurred in mscorlib.dll but was not handled in user code</p>
  <p>Additional information: Exception from HRESULT: 0x800AC472</p>
  <p>If there is a handler for this exception, the program may be safely continued.</p>
  </blockquote>
  <p>How can I prevent this error in an asynchronous method?</p>
  <p>Any help would be appreciated.</p>