Hi Dan,
I haven't done anything new in settings or recent updates as it's current.
When I went to storage I could see it was not detecting the 4TB hard drive.
I opened up the nvr and made sure all connections to the hdd were secured, and powered-up the unit.
Same outcome.
I unplugged the cables to the hdd and plugged them in again and the hdd was detected!
It was full.
I re-formatted and initialized it again and all is good.
I cannot seem to understand why this happened and also the strange thing is my hdd setting are on to overwrite when full?
I'm thinking maybe something is strange with the hdd and will have it replaced as its under warranty still.
What's your opinion Dan?