When I try to do it via the API I get a more descriptive response 

Cannot export Virtual Disk. Disk configuration (${volumeFormat} ${volumeType}) is incompatible with the storage domain type.

Makes sense, it was imported from 4.1

So now the question is how can I fix this storage domain

On Fri, Jan 26, 2018 at 6:43 AM, Donny Davis <donny@fortnebula.com> wrote:

I am trying to copy a disk that was from a storage domain that was imported from 4.1 to a newer storage domain and this exception is thrown in the UI

Uncaught exception occurred. Please try reloading the page. Details: Exception caught: (TypeError) : Cannot read property 'g' of null
Please have your administrator check the UI logs