It first happened when I removed the 3TB drive from the chassis to replace it with the new 5TB drive which caused a Storage Spaces rebuild and all of the drives started to chatter away copying blocks around and about half-way through the rebuild, the server stopped responding to pings. I jumped on to the IPMI remote console expecting to see that I was using so much I/O on the rebuild that it had decided to stop responding on the network but in actual fact, the screen was blank and there was nothing there. I tried to start a graceful shutdown using the IMPI but that failed to I had to reset the server.
When Windows came back up, it greeted me with the unexpected shutdown error. I checked Storage Spaces and the rebuild had resumed with no lost data or drives and eventually (there’s a lot of data there) it completed and I thought nothing more of it all until New Years day when the same thing happened again. This time, after restarting the server and realising this was no one off event, I changed the Startup and Recovery settings in Windows to generate a Small Memory Dump (256KB) otherwise known as a Minidump and I also disabled the automatic restart option as I wanted to try and get a chance to see the Blue Screen of Death (BSOD) if there was one.