Our library has been having the same basic problem with the digitizing pads from 3M -- Now Bibliotheca -- from when we started with Millennium over a dozen years ago until now when we are running Sierra.
The problem is that the pad reads the barcodes just fine, but has difficulty sending them to Sierra. It will work fine for weeks at a time sending the barcodes to whichever application has focus, just like the keyboard does. This is perfectly workable. Then somehow it switches itself to wanting to send to a particular specific application, but the list of applications never has Sierra listed.
I am sure there is some specific little flag or checkbox I am missing, I cannot really believe it is completely random but having read the help file, having tried the CTRL-ALT-T method, I am still stumped.
The computer that is having trouble today is running Windows 7 Enterprise, but I have had this problem from XP all the way to Windows 10.
I just reinstalled the software: 895 Pad Staff Workstation v1.60.004.0 Installer