New HDD degraded during rebuilding and stop rebuild. with no manual re-build button shown

dear guys,

I have mycloud mirror RAID1 with two 6T drives.

My HDD#1 drive failed so i insert a whole new drive to replace. it rebuild automatically but stop at 6%. the new HDD shown degraded!! so i do a quick check the result is ok.

RAID page says degraded but Drive state page say both healthy. (I know many people have this issue!)
and both LED are BLUE.

Now the problem is, I can’t find a button to manual re-build the HDD#1. the below manual rebuild button is not shown.

Now I have shutdown the NAS. what should I do next?
just restart to let it auto-rebuild again? or click change RAID mode?
Will I loss my important data in either way?

Q1. Can I start NAS with HDD#2 ONLY so I can backup my files?

Q2. If I startup with two drives, will NAS get confused which one to be rebuild? i worry it will auto rebuild and do wrong direction. should I format it in Windows first so NAS will know easier HDD#1 is new to be rebuild.

Q3. can i plug good HDD#2 to windows PC to backup?

thanks for your help.

best regards,

Hi Calvin,
i have the same issue. How did you solve? I signaled to the WD support but i didn’t receive yet an answer


no, i don’t have solution yet.
I just connect the working HDD and backup all data.

I have bought another NAS to save data.


paoloberry via WD Community <> 於 2021年8月26日 週四 下午5:13寫道:

tks Calvin, but did you signaled that issue to the support? If you did and you didn’t receive an answer since two years, i think that i can leave any hope to be answered by the WD tech support :frowning:

Hi Calvin, since the WD support didn’t help me but only said to restore the setting, I solved by myself rebuilding the raid using SSH and mdadm manually adding the missing disk and the raid has been recovered.

Hello pauloberry im having a RAID issue as well but what does rebuilding the RAID by SSH and mdadm manually adding the missing disc mean?

You should connect to the WD my cloud by SSH . Do you know what is SSH? You should enable SSH by the settings.
After that, you can connect using sshd user and issuing “mdadm --detail /dev/md1” to check the current raid status

Hello Pauloberry,thanks for getting back to me.
No im sorry but i do not know what those abbreviations stand for.