I’m curious as to what would happen either if MFS is closed or there is an unexpected restart of the PC.
I had an utility power outage during the creation of the rolling cache, though my laptop power(battery) helped.
I don’t think anything serious is happening because the cache is being filled with data by the MSFS.
If I noticed the interruption, I would not shut down the Sim, but delete the cache immediately and generate it again.
I think that the rolling cache resides on a virtual hard drive (basically a big file on your hard drive), and this gets prepared every time you adjust its size.
In case of a power outage the worst outcome (saving hardware issues) is that the file will become unreadable and you’d need to update the size of the rolling cache again to have the system make a new one.