Unable to create a RAID array after disk replacement

[ksburk]

   

Have a TerraStation Live 1TB.  Firmware 2.14-102.  One of the 256GB hard drives failed.  I replaced with a 500 GB hard drive.  The manual implies that the unit will ignore the extra capacity when setting up the RAID 5 array.

 

The unit errors out each time I try to create a RAID 5 array.  The initial error that is displayed is "The File System or Disk Format is not readable" 

 

I am able to create a RAID 0 and RAID 10 okay but not the desired RAID 5.   I have reformatted all disks several times.  I have deleted and tried to rebuild the arrays several times.  I tried redoing the firmware but the updater only states that the versions are identifical so no need. 

 

Do the hard drives have to be equal capacity?  If no, then suggestions?

 

Thanks