Network connection is lost after migrating from SEP 11.x to 12.1 RU2 on Windows 7 and 2008


Article ID: 157600


Updated On:


Endpoint Protection


Migration to Symantec Endpoint Protection (SEP) 12.1 appears successful, but if the machine is allowed to run for several hours and rebooted again it will lose all network connectivity. Ipconfig shows no network adaptors.




The solution for this issue is contained in Symantec Endpoint Protection 12.1 RU2 MP1.  Upgrade affected clients from SEP 12.1 RU2 to SEP 12.1 RU2 MP1 to take advantage of this fix and many other enhancements and improvements going forward. For information on how to obtain the latest build of Symantec Endpoint Protection, read How to obtain an update or an upgrade for your Symantec corporate product.

Note 1: To avoid the issue, consider using the autoupgrade feature to migrate directly to the 12.1 RU2 MP1 build (skipping 12.1 RU2). Autoupgrade is the only supported method to migrate directly to the maintenance patch.

Note 2: Upgrading directly to 12.1 RU2 MP1 will prevent the issue from occurring, but will not fix any clients that are currently impacted by the problem. Please follow the workaround steps listed below to correct any clients that were already impacted by this issue.



Should an upgrade not be immediately possible, this issue may also be resolved before the second reboot by running the latest version of CleanWipe. Please contact support for access to the latest download.

Once networking has been lost:

  1. Add the firewall component, if it is not present, and reboot.
  2. Remove the firewall component, but do not reboot.
  3. Back up the registry and delete the following registry keys if present:
    • HKLM\SYSTEM\CurrentControlSet\Control\Network\{4d36e974-e325-11ce-bfc1-08002be10318}\{72891E7B-0A3D-4541-BDCB-3DA62E25B6A8}
  4. Reboot the system and networking should be restored.


Applies To

Windows 7 32-bit or 64-bit
Windows 2008 R2 64-bit

Migrated from SEP 11.0.7300 with Network Threat Protection (NTP) installed.