Have this problem too.
Product Part: LS420D0402-EU
Serial Number: 80059434501887
Description: LS420D NAS Raid0 Array Failed
Problem Details: cannot mount Raid array
always shows checking
it seems hard drives are normal
it has been 3 days it keeps checking.
I only have 2*2TB disks on Raid 0, dont know how to recover the data cause it is very important
It shows like this
Somebody help me!