Windows 7 - Verbatim 1TB External drive not recognised on boot

Can I examine it with another program maybe? I still don't understand why it's not loaded on startup, then gets loaded on off/on procedure within windows.

Backup all the data on your Verbatim HDD and then format it. See whether it resolves the problem.

Is it a USB 3.0 drive? Does the PC have USB 3.0?

What are the drive diagnostics you ran on it? Have you contacted Verbatim Tech Support for help if the drive is less than a year old?

I've contacted Verbatim and they told me that the drive should be switched off before powering down the pc, then switched on again when the pc is powered on again and windows loaded. Doesn't make much sense to me, would be a big hassle to stay disconnecting and connecting usb devices in such a way.

Formatting the drive didnt resolve the issue either.

Try wiping the HD using Diskpart Clean Command or Partition Wizard

This works in cases where it has accidentally been bootsected so that it will boot, but there can be other corruption in the boot sector as seen in cases where a HD will block BIOS POST until wiped.