Players getting the error “Can only be used while mounted” when trying to use their D.R.I.V.E. on the PTR can fix it by going to Mobber and reselecting their ride’s attachments.
D.R.I.V.E. Guide
Reselecting Attachments
The issue seems to stem from Blizzard resetting everyone’s D.R.I.V.E. attachments with this build, leaving mounts in an impossible state. To fix it, you need to head to the D.R.I.V.E.
