[Samba] Samba reporting "disk full" to Windows 10 client

Wed Jan 15 11:29:20 UTC 2020

I'm sure this a FAQ! I have a shared RAID drive of about 22TB. It's got just
under 4TB used.

This is shared using Samba to some Windows systems

Today while I was running a backup using Macrium Reflect it reported "disk
full" when it went over the 4TB mark (even though there's LOADS of space
available).

So how do I configure Samba so that Windows 10 systems handle >4TB shares?
Or if the change needs to be at the Windows end what do I need to do.

Thanks
David