When checking the ..\Trend Micro\ControlManager\WebUI\download\activeupdate\pattern folder, it contains a lot of old/invalid pattern files.

Normally, those old pattern files should be auto-removed after downloading a new pattern. However, due to unexpected issue, the deletion process was obstructed.

To address this issue, do the following:

1. Go to ..\Trend Micro\Control Manager\.
2. Using text editor, open aucfg.ini.
3. Add the following setting:
   [common]
   delete_invalid_packages=1
   delete_directory_list=pattern;
    

   We only recommend to keep this setting if you frequently encounter the issue.

    
4. Restart Trend Micro Apex Central service.
5. Perform a manual update. After the update, the old/invalid file should be purged.

If the issue persists, contact Trend Micro Technical Support.