A customer had an issue where the dtSearchDebuLog.log logs were being generated very frequently.

An error in the logs was:

• Logging error writing to previous logdebuglog.log
  Error: Access denied. (5)

A temporary fix was provided by following this article:

https://www.sagecity.com/sage-global-solutions/sage-crm/b/sage-crm-hints-tips-and-tricks/posts/how-to-get-the-indexer-service-keyword-search-running-again

but the logs started to generate again.

If you will navigate to this location:
C:\Program Files (x86)\Sage\CRM\Services

you will find dten600.dll and dtSearchWedge.dll which are responsible for the logs being generated when a keyword search is performed.

The root cause for this issue happens to be the IIS settings.

If you have "Anonymous Authentication" enabled in IIS then it should be changed to "Application pool identity". You will need to restart the Application pool. The logs will no longer be generated.