To the point; Do not clear your cookies or temporary internet files.
I was trying to setup my old laptop to run lightbox without choppy audio video. So I tried multiple browsers (Chome, Firefox and IE)
After updating Firefox and IE. I only had 1 device slot left.
How could this be. I only used one physical computer. So I decided to Clear cookies and Internet files for Chrome. Low and behold Lightbox to many devices registered you can not register more.
I have escalated this to Lightbox operations team. But using Browser info written to a cookie is a poor way of registering a device.