Unexpected volume rebuild taking forever

I noticed today that my WD My Cloud Mirror (Gen 2) was very slow and unresponsive. It is connected by Ethernet to the latest generation AirPort Base Station and I access it over WiFi. I logged into the web interface and discovered that it is rebuilding Volume_1 (I do not know why it needed to do that – I did not initiate it). It has been rebuilding for hours, it only 0.7% done, and it is estimating that it will finish in 61132 minutes. Is there something wrong and is there a way to speed up the rebuild?

To answer my own inquiry, late last night the rebuild sped up dramatically and it was done when I awoke this morning.

I’m glad the rebuild process was completed.