How does MetaDefender Core determine the runtime nginx.conf location on Windows?

Issue:

After upgrading to MetaDefender Core 5.17.1 or later (see Windows Temporary Folder Path Changes for SYSTEM Account for details regarding the Local System account), or configuring the MetaDefender Core service to run under a different Windows account, users may be unable to locate the runtime nginx.conf file.

Historically, the runtime configuration was commonly found under:

However, depending on the MetaDefender Core version and the account configured to run the service, the runtime configuration may be generated in a different location.

Main cause:

The runtime nginx.conf is generated automatically during MetaDefender Core service startup.

The location is determined by the temporary directory resolved for the account configured in the Log On As setting of the OPSWAT MetaDefender Core service.

For services running as Local System:

For services running under any Windows user account, the runtime configuration is generated under the temporary directory resolved for that account.

For example:

The exact location depends on the value of the account's TEMP environment variable.

Resolution:

Step 1. Verify the account running the MetaDefender Core service

Open:

Locate:

Open Properties → Log On and identify the account configured to run the service.

Step 2. Locate the runtime configuration

If the service runs as Local System:

• MetaDefender Core earlier than 5.17.1

• MetaDefender Core 5.17.1 or later

If the service runs under a Windows user account, navigate to that account's temporary directory.

Typical example:

or

The runtime directory contains files such as:

• nginx.conf

• ometascan-nginx.pid

• NGINX temporary directories

Step 3. If the directory is missing

Restart the OPSWAT MetaDefender Core service.

The runtime configuration is regenerated automatically during service startup.

Notes:

• The generated nginx.conf is the runtime configuration used by the embedded NGINX instance.

• The runtime nginx.conf should not be modified directly.

• If custom NGINX configuration is required, follow the supported method for loading additional NGINX configuration files.