If you try to delete all the files and folders inside the Windows "Temp" folder (located at %temp%), you might end-up encountering a few files which cannot be deleted as they are being used by some open Windows application or user. The solution for this is to use an file-unlocker utility like "Unlocker" to disable all file-open handles and delete it. However there are some "invincible" files which will recreate even after forceful deletion. One such file is FXSAPIDebugLogFile.txt, luckily it's no malware and just a log file associated to Windows Print and Document Services - and if you don't use Windows printer and fax network sharing features, can be safely disabled as shown ahead.
To get rid of this automatically created log file, we need to disable Windows Print and Document Services - before disabling make sure you read the linked article so you wont endup with broken usability.
To disable navigate to Windows Control Panel -> Programs -> Turn Windows features on or off and uncheck the Print and Document Services option, now let Windows complete the process and restart your machine. You will no longer see the FXSAPIDebugLogFile.txt file in your temp folder.