"Must be primary partition"... except it already is.

[baffleblend]

I'm trying to set up a Windows 2 Go installation on an external HDD. All I need to do is install the boot entry. But the deployment fails, telling me that I need to convert the partition to a primary. partition.

The trouble is, the partition I'm trying to deploy it to is already primary. In fact, it's the only partition on the drive in question. So at the moment, there's nothing I can do.

The drive is a 4TB HDD.

 

[Terry60]

If it's a 4TB partition, then the drive can't be MBR. It must be GPT.
That's presumably what is being objected to.