I was recently trying to decommission a Storage drive D:\ from an Exchange server

All the Databases and logs had been moved off apart from one folder D:\ExchangeLogs\OfficeGraph\GraphStorageCompactLogs which could not be deleted and it was being used and w3wp.exe ( IIS )  locked a file 

Per this it’s actually ” Graph API is for hybrid Exchange 2016, since you don’t have Hybrid mode, I suggest to disable Graph API service to see if it will prevent that error events happening. 

https://blogs.msdn.microsoft.com/deva/2017/07/22/use-microsoft-graph-api-to-reach-on-premises-cloud-users-of-hybrid-exchange-2016/

There is no way to configure this, so in the end, I have to remove the drive manually