There are two causes of this error.

1. The software is detecting an external or removable camera instead of the Desk scanner.
2. The wrong version of the software is being used for the scanner hardware.

To fix the first situation unplug the external device from your computer and retry after closing and restarting the Desk software.

To obtain the correct software use these links for that hardware that you have.

For the IRIScan Desk 5, 5 Pro  
IRIScan Desk 6 and 6 Pro
https://www.irislink.com/support/FAQ/iriscandesk6

For the IRIScan Desk 7 Pro and Business

https://www.irislink.com/support/FAQ/iriscandesk7