The new docs.trellix.com offers a modernized UI and AI-powered features like conversational searches. Content is currently available only in English. Other languages will be available in mid-October 2026. We hope you enjoy the new experience.

Press CTRL+K to open search

Windows errors

  • Published on Sep 13, 2026
  • 1 minute(s) read
Prev Next

Windows displays these error messages when an unexpected condition occurs while installing Trellix Endpoint Security (ENS) 26.x. Use this information to find an explanation of the condition and a solution.

If you are getting an error message that isn't listed here, contact Trellix Technical Support.

Message

Description

Solution

Installation failed.

The installer couldn't install Trellix ENS. It made no changes to the system.

See MsiExec.exe and InstMsi.exe Error Messages for descriptions of specific error codes. If the issue persists, contact Technical Support.

Threat service has stopped. Restart it now.

After restarting a system, this message appears in the Virus & threat protection page in Windows Defender Security Center. Virus Scan tries to send the Trellix ENS security status to the Security Center service. This fails because the Security Center service is not in a running state immediately after a restart. After about two minutes, when the Security Center service is in a running state, Threat Prevention successfully sends the security status and the message no longer appears.

Ignore this message when displayed temporarily after a restart. The security status is automatically corrected about two minutes after the restart.

Related articles