Hi mdi,
So the issue is the tool that you used to create the partition ( or maybe, you format again the ntfs disks without changing their code type...)
It set as code type the code 0700 which is a window code instead of the code 8300 !
So in putty, change their code by using gdisk and the t command in gdisk.
Then, delete also the folder /share/1000/data1_1
To get a clean NAS status, reboot it and see if it succeeds to mount now the disks :whistle
The disks were formatted with Linux Mint, with the gnome disk utility.
From a terminal I used the dd to zero the first part of the HDDs, to make it easier to format them (dd if=/dev/zero of=/dev/<disk> bs=1M count=100). Then I used the gnome disk utility to:
1. format with GPT
2. create a new ext4 primary partition
Seem to be a complicated way to format the disk :mrgreen:
in gdisk :
Just delete the partition table (command o)
create a partition (command n) with the right code :8300
format the disk : mkfs.ext4 -j -m 1 /dev/sdc1
That 'all