Slow disk checking.. Going on 3 weeks

[Metzen]

I have a TS-RXLB90 with 4x1.5TB drives in a RAID5, firmware 1.50. Recently I started getting a notice that I had a disk error on disk 1. I then started a check disk on the array, which started on Jan 17th and is still going. How long is this supposed to run for?

[Jotin]

Maybe a day or so. There is definitely a problem with that disk. Power down the unit, remove the disk and replace it.