In your Exchange 2016 environment, you might be running CU8 or CU9 but keep noticing the following warning below log about every 6 hours in the application log:
Log Name: Application
Date: 7/17/2018 6:10:23 PM
Event ID: 3028
Task Category: Extension
Scenario: ProcessKillBit. Failed to read killbit list file because of exception System.IO.IOException: The process cannot access the file
‘C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\owa\prem\15.1.1466.8\ext\killbit\killbit.xml’ because it is being used by another process.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
at Microsoft.Exchange.Data.ApplicationLogic.Extension.KillBitHelper.TryReadKillBitFile(Int32& refreshRate, DateTime& lastModifiedTime)
I have been trying to figure out what is causing it to no avail, it is probably a bug in the CU or its looking for something which is not set.
I have not noticed any issues with Exchange at present, so hopefully it is safe to say we can ignore this for now.
From what I understand from the Team is that there is no fix at present, hopefully it will be addressed in a future CU release.
Hope it helps.