BDMV Folders not recognized by Z9X

My bad for miss quoting, I am just getting into the world of NAS so still green on the terminology and such.

 

I run my hi-res music on one hdd and my 4k fims on another (both 8tb), which I swap about in the Zidoo's internal hdd bay. Non-lossless music and lower resolution fims are stored on 2 NAS's both RAID enabled. Have another NAS and an Egreat E11 for photo viewing.

It's just my 8tb film hdd is almost full now and I need to source something larger - just had a Zidoo DAC-Z8 delivered so funds are a little tight right now

 

@Nice Monkey Would you be so kind to help me with the math here? I am most likely overthinking this but:

Looks like in TBytes, the drive is already pretty close to 17.5 TBytes and only a bit over. Would this just take a very small chunk to make things smoother? PS, I am going to empty the whole thing out first and then reformat but just wanted to make sure how much I need to take off. Thanks in advance!

18,000 GB = 17.578125 TB

So I need to take off 0.078125 TB? Remaining with 17.5TB?
0.078125 TB = 80 GB

Or take an entire 0.5TB off? Remaining with 17.5 TB in theory?
.5 TB = 512 GB (in binary)

Appreciate all the help you can provide!