I was having trouble getting WOL (Wake On Lan) to work properly with my WD PR4100 NAS, so I began to investigate various network setting so I could locate the culprit. Eventually, I isolated my WOL (Wake On Lan) problem to my router, which had assigned a DHCP reservation to another device which previously had the same IP address as the NAS. This somehow caused a conflict that resulted in the WOL (Wake On Lan) packets not reaching the NAS.
During the process of trying to solve the WOL (Wake On Lan) problem, I inadvertently turned VLAN on from within the NAS dashboard. VLAN requires special network configuration settings for it to work properly, so turning it on resulted in my not being able to access the NAS, either by name or IP address. It was early and I was still on my first cup of coffee so I was on autopilot. I simply wanted to watch a movie, not troubleshoot a network.
Eventually the NAS assigned itself an APIPA (Automatic Private IP Addressing) IP address 169.XXX.XXX.XXX, which has a default class B subnet mask of 255.255.0.0. Long story short, APIPA addresses are self-assigned by a device (the NAS) if the DHCP server (Router) is unable to assign it an IP address. While it’s possible to access the NAS using the 169.XXX.XXX.XXX IP address, doing so requires special network configuration settings on the client device (computer, phone, etc) so it can communicate with the NAS using the 255.255.0.0 class B subnet mask. That said, the easiest thing to do is to reset the NAS using a 4 second reset.
When the reset procedure is complete, DON’T FORGET TO REASSIGN AN ADMIN PASSWORD. Also, the 4 second reset will NOT result in data loss.
[quote]The 4 Second Reset (Reset with Power On) will reset the following:
Admin Password (No password by default)
Network Mode (Default = DHCP)
Note: The 4 Second Reset will only reset the Admin Password. It will not reset the Admin User Name. In order to reset the Admin User Name perform a 40 Second Reset.
To execute the 4 Second Reset:
With the power on, using a paperclip or narrow tipped pen, press and hold the reset button for at least 4 seconds. The reset process will cause the device to reboot and may take up to 5 minutes to complete. Please wait until the Power LED is solid blue, indicating the device is ready to use.[/quote]
How to reset a My Cloud device:: https://support.wdc.com/instructions/?ID=10432&lang=en