Open NVDA settings, select Advanced
Tick 'I unserstand...'
Tick 'Enable loading custom code'
Open developer scratchpad directory

Drop the braille driver files in here:
C:\Users\<username>\AppData\Roaming\nvda\scratchpad\brailleDisplayDrivers

https://gitter.im/nvaccess/NVDA#

trumpton @trumpton Apr 25 21:15
I'd like to test how a QT application works with NVDA, but don't have a Braille display. With previous versions, I used the BrailleViewer.py and placed it in the brailleDisplayDrivers folder. This doesn't seem to work with NVDA 2019 - has anyone got any hints?

Reef Turner @feerrenrut Apr 25 21:17
You'll need to enable the scratch pad directory (see the advanced panel in the setting menu) and place the brailleviewer.py file in the brailleDisplayDrivers folder in the scratchpad directory.
This was changed because of the security and stability concerns of having these files (often forgotten about by users) being loaded. They should really be packaged as addons. We plan to integrate the braille viewer eventually.

trumpton @trumpton Apr 25 21:21
Many thanks - works great after a restart !!!

Amanullah0123 @Amanullah0123