So, unraid newby here so please be gentle. Things have been going great last few months, I had thrown a couple of old discs (1.5TB and 3tb) in with the 16TB parity and a 14tb drive. I am also running to 1TB NVMEs in RAID 0. I filled the 14tb drive and decided I wanted to swap out the 1.5TB, add a 18TB that I bought and then flip the 18TB to be the parity to give space for further expansion. Following some guides I removed the 16tb from the pool and restarted, and then disconnected the 1.5tb and connected the 18tb. Now, I recognise that that was too much all at the same time, I thought that the 1.5TB was unused, but clearly it was not, so I reverted, disconnected the 18tb and reconnected the 1.5tb with the 16tb drive back in as the parity drive. So, I am effectively back where I started, which is fine. However, I have to rebuild the parity drive and this runs for about 36 hours, but every time this completes, the server becomes inaccessible on the network (cannot ping it via cmd on local windows pc), I reboot all network equipment and this does not resolve matters, forcing me to manually hard shutdown, which then requires the server to rebuild the parity drive again, and my groundhog day experience resumes. Anything that I can do to get over this hump? Many thanks in advance.

Attach Diagnostics to your NEXT post in this thread. 

Diagnostics attached. Apologies for omitting.

tower-diagnostics-20241021-0953.zip

I solved this - found out that it was overheating. Got that fixed at a HW level and now stable as a rock again.