Hello,
Thank you for posting in Q&A forum.
The "NOUSER" username you observe in the Windows logs can be the result of a number of situations. Here are some possibilities why you might see "NOUSER" in your logs:
- System or service accounts: Sometimes, system processes or services that run without a specific user context may appear as "NOUSER" in the logs. These are typically processes that need to run regardless of whether a user is logged in or not.
- Anonymous users: Events triggered by anonymous logins or guest accounts may appear as "NOUSER".
- Invalid username: When the event occurred, the system attempted to log a username that did not exist. This could be due to a typo, a deleted user account, or a changed username, among other reasons.
- Malware: In rare cases, this could be a sign of malicious activity. If you suspect this, it is recommended to run a full system scan with up-to-date antivirus software.
If you are concerned about this log entry, or it is causing a specific problem, then you can check the specific event ID and description associated with the "NOUSER" entry in Event Viewer for more context.
Best Regards,
Yanhong Liu
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