Why does Bleu light not come on?

I could no longer log into the dashboard and rebooted the WD MyCloud unit.
Surprisingly, the white dashing LED light went out after a while (no light at all) but the normally solid bleu light has not come on.
I have access to the unit and entered the new password. I also I have access to the files, so everything appears to work as far as I can see.

Any idea what could cause this bleu light not to come on and how to fix this problem?

I read in the knowledge base:

A system restore, reboot, or an abrupt loss of power on a My Cloud device may result in a longer than expected Powered on and Ready phase. This may be due to the file system check process running.
Important: Performing a System Restore or Power Cycle, or an other interruptions will force the file system check to start from the beginning.

I rebooted the unit yesterday night by 11:00 PM; no light was showing at all this morning when I plugged in the LAN cable. It has been at least 3 hr since I plugged in the LAN cable; still no bleu light (no light at all).
This is a 2 GB drive but almost empty. How long does this file system check usually take.

Thanks for your help

the blue light is done by a led light. Led light can vanish because fail working. Mine is also gone, but when i boot the other lights are working and the unit is working as it is suppose to do. I do not think you can fix it. It dos require a technical workmanship to fix and replace the blue led.

Thanks Jorn,

I assumed the LED would be a multi-color LED, but even in that case there could be multiple color sections on the same LED chip and the bleu one could have failed.

I was hoping for a software fix or something else easy to do, but if the bleu LED died there are no easy options.