This worked for me.
***Can You Reset A Dyson Battery?***
***Yes, it is possible to reset your Dyson battery***. That is usually done as a troubleshooting step when the vacuum doesn’t run, even when the battery is charged, and you’re pulling the trigger.
***To reset your Dyson battery, you’ll have to:***
# ***Unplug the charger from the wall.***
# ***Plug the charger back in again.***
# ***Connect the charger to the Dyson vacuum.***
# ***Pull the trigger and hold for 20 seconds, even though the ++vacuum doesn’t turn on++.***
# ***Let go of the trigger. Remove the charger from the vacuum and continue using it like normal.***
This combination of steps will reset the battery and get your Dyson vacuum running normally again.