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Common causes of license loss - MDT25

Updated on 16 September 2026 tcpMDT Leer en español

7.3 COMMON CAUSES OF LICENSE LOSS

The following are the most common situations that can cause an activated Sentinel license to be permanently disabled:

Formatting or reinstalling the operating system without having previously transferred the license.
Cloning of the disk or operating system, either to another physical computer or to a virtual environment.
Conversion of the physical computer to a virtual machine (P2V) or creation of system images in a virtual machine (VM) format.
Restoring system backups (images or snapshots) to hardware other than the original.
Substantial modifications to the computer's hardware, such as changing motherboard, CPU, storage controllers, or network adapters.
Major operating system updates or repairs that alter internal hardware identifiers. Upgrades from Windows 10 to Windows 11 may also be affected.
Running in unauthorized or different virtual or emulation environments than the computer where the activation took place.

The Sentinel license is associated using a unique computer fingerprint. If any of the identifying components change, the license is no longer valid and cannot be recovered, even by reinstalling the software.

Before performing any of the actions described, it is recommended to:

Use the license transfer tool included with TcpMDT-25 to transfer the license to another computer.
Verify that the transfer has been completed correctly before proceeding with the operation.

RISK: TRANSFER BLOCKED BY THE FIREWALL OR BY COMPANY POLICIES

The recommendation above —transfer the license before formatting, cloning, virtualizing or changing the hardware— can only be followed if the computer has outbound access to Aplitop's license server. The automatic transfer, like the initial registration or activation of a standalone (single-seat) license, requires a connection to https://licenses.aplitop.com on port 443 (TCP/HTTPS).

In corporate environments this connection is frequently blocked without the user being aware of it. The most common causes are the perimeter firewall or the computer's local firewall, domain and Active Directory policies (GPO), a proxy server requiring authentication, web category filtering, antivirus software that scans HTTPS traffic, or an SSL inspection system that replaces the server certificate.

Consequence: if that outbound connection is blocked, the automatic transfer does not complete. If the computer is then formatted, cloned or its hardware modified, the license becomes permanently unusable and recovering it may involve additional costs.

Therefore, before carrying out any of the operations described in this section:

Confirm with the company's IT manager that the computer can reach https://licenses.aplitop.com on port 443, and request that it be added to the firewall, proxy and SSL inspection exception lists if necessary. Remember that a transfer involves two computers: the one releasing the license and the one receiving it.
Perform the transfer and check that you have received the transfer code, which is also sent by email.
Only then format, clone or modify the computer.
If that outbound connection cannot be authorized, use the manual transfer described in 5.2 SOFTWARE LICENSE TRANSFER (MANUAL) - MDT25 instead of the automatic one.

This requirement applies to standalone licenses. Network licenses managed by a license server do not need this connection.

IMPORTANT: APLITOP will not be able to restore a lost license for reasons unrelated to an activation system error.