If you have a license that is about to time-out, you will see a license expiration warning message when you open an application using this license.
If you wish to suppress this message:
You must have installed the ArcObjects Developer Kit (using a complete or custom install).
Log onto your computer with Administrative privileges.
Go to your installation location and click on the following executable:
<Drive:>\ArcGIS\arcexe81\ArcObjects Developer Kit\Utilities\VBAdvancedSettings\AdvAMSet.exe
Choose the Miscellaneous tab.
Uncheck the box under Timeout Warnings.
Click Close to close this application.
The change is automatically applied. You will no longer see the warning messages, however the license will still expire on the time-out date specified in the warning message.