Sometimes when the file share that is hosting the witness gets taken offline the exchange server will report that the File Share Witness has failed and it will not be able to bring it back online and give back the reason "Access is Denied"
You know full well that the share permissions have been set properly, giving the Exchange Trusted Subsystem Full Access to the share and adding the same user to the local Administrator group but it still doesn't work.

I feel like GPU passthrough is much easier done on other hypervisors like ESXi but alas... I can't be bothered to migrate my entire environment to ESXi.
I put some time and effort in trying to figure out how this is done, i'm running Hyper-V Server Core 2016 and the RemoteFX option isn't enabled or can be enabled at all.
Something about Microsoft and security leaks. But thank god it's still possible to configure GPU passthrough to your Hyper-V VM's!

By default on a fresh new installation you will get an error when trying to move VM's between two Hyper-V hosts.
Something in de line of "no credentials are available in the security package Hyper-V"
If I remember correctly, this has to do with Microsoft changing the way the servers communicate to make it more secure. Sadly Microsoft doesn't automatically configure this for you even in the 2019 version of Hyper-V.

Somtimes a retention policy isn't enough, can't use it or you simply just need to run it once in your lifetime.