Time Machine setup on NAS using WD EX2100

Greetings seamu07,

In order to back up with Time Machine, you'll need to change the storage device.

"Select your storage device in Time Machine settings

When you connect the storage device to your Mac, your Mac might ask if you want to use it for Time Machine backups. If it doesn't ask, follow these steps.

1) Open Time Machine settings:

• macOS Ventura or later: Choose Apple menu  > System Settings, click General in the sidebar, then click Time Machine on the right.
• Earlier versions of macOS: Choose Apple menu  > System Preferences, then click Time Machine.

2) In Time Machine settings, select your external storage device as your backup destination:

• macOS Ventura or later: Click the add button (+), then follow the onscreen instructions.
• Earlier versions of macOS: Click Select Backup Disk, then follow the onscreen instructions. 

3)If the storage device contains Time Machine backups from another Mac, you might be asked to claim the existing backups so that they become part of the backups for this Mac. Or you can choose to start a new backup instead." Back up your Mac with Time Machine

We hope this helps you back up to your hard drive.

Sincerely.

Understood seamu07,

Per the article Backup disks you can use with Time Machine - Apple Support, "Many third-party NAS devices support Time Machine over SMB. For details, check the documentation for your NAS device." So you'll want to check with WD regarding those settings.

Cheers!