Hello,
My Book blue led flashing quickly in continious. I’ve tried to make a soft reset (4s) and hard reset (40s), but when I plug DC on My Book blue led directly flashing quickly.
I can’t see My Book on Windows Explorer, Network explorer.
My Book is not on warrantly anymore.
Do you have a WD My Book or a WD My Cloud? They are NOT the same device. You have posted in the My Cloud subforum. If you really have a My Book you may need to search for the proper subforum.
If you have a My Cloud device then use the forum search feature, magnifying glass icon upper right, and search for flashing blue LED there are a number of past discussions on troubleshooting steps to try.