Upgrade Photoshop Elements from 2019 to 2021

[ColinWH]

I have just purchased the Elements upgrade for Photoshop Elements 2021.

However, although I have Elements 2019 already installed and registered, I cannot register the upgrade and it insists I can only run it in 'Trial Mode'

I welcome any suggestions regarding how to register this upgrade.

Many thanks,

[ColinWH]

Hi, I have just rebooted the Windows 10 machine and it now recognises that \elements is registered. 

Unusual that a reboot is required, but not the end of the World!