Fix 0X000019DE ERROR_LOG_POLICY_CONFLICT on Windows Server

Quick answer

Run wevtutil gl "Log Name" | findstr /i policy to see the policy, then wevtutil sl "Log Name" /ms:10485760 to reset max log size if it's restricted.

What's happening here

I know this error is infuriating — you're trying to write to a log, and Windows just says no. The 0X000019DE error means a policy on that specific log (like Security, Application, or System) prevented the operation. This tripped me up the first time too, during a Windows Server 2019 migration where a group policy had locked the max log size to 20 MB and an app tried to write beyond it. The policy can come from local security settings, domain group policy, or even a third-party backup tool that modifies log retention. The error message is vague, but the fix is straightforward once you identify the log and the policy constraint.

Fix steps

Identify the problematic log
Open Event Viewer (eventvwr.msc). Look for which log (e.g., Security, Application) triggered the error. The error usually pops up when trying to write to a log, so check the one your app or system is hitting.
Check the current policy
Open Command Prompt as admin. Run:
```
wevtutil gl "Security"
```
Replace Security with the actual log name. Look for maxSize, retention, and autoBackup settings. A retention set to true with a small maxSize is the most common culprit — it means the log can't overwrite old events and won't grow beyond that size.
Reset the log size
Run:
```
wevtutil sl "Security" /ms:20971520
```
This sets the max size to 20 MB (adjust as needed — 50 MB for 52428800). The key: set it higher than whatever policy is blocking you. For domain-joined machines, the group policy might override this, so you'll need to check gpedit.msc next.
Verify group policy
Run gpedit.msc and go to Computer Configuration > Administrative Templates > Windows Components > Event Log Service. Find the policy for your log (e.g., Specify the maximum log size for Security). If it's Enabled, set a value larger than what you set via wevtutil. Or set it to Not Configured to let the local setting take over.
Clear and retry
After changing the policy, clear the log with:
```
wevtutil cl "Security"
```
Don't freak — this wipes old events but immediately fixes the block. Then retry the operation that failed. If it still errors, reboot the server to ensure the policy refreshes.

Alternative fixes if main one fails

If the above doesn't work, check if a third-party backup or log management tool is locking the log. I've seen Veeam and SolarWinds set custom log policies via registry under HKLM\SYSTEM\CurrentControlSet\Services\EventLog\Security. Look for keys like MaxSize and Retention. Delete or modify them manually, but back up the key first. Another rare case: the log file itself is corrupted. Run wevtutil epl Security backup.evtx to export, then wevtutil cl Security and re-import. If nothing works, check for malware that deliberately blocks event logging — scan with Defender or your AV.

Prevention tip

Set a baseline log size via group policy for your entire domain. For Windows Server 2016 and later, I recommend 1 GB for Security logs and 500 MB for Application logs. Use wevtutil gl in a startup script to audit all logs monthly. This error usually only hits once, but if you're running backup software that tweaks logs for performance, whitelist that log in the policy to avoid lockouts.