Hi @tw2018, sorry to hear about your troubles. As you are probably aware, the Tobii REX tracker has been discontinued so our latest Tobii Eye Tracking Software is not compatible with the REX device and we, therefore, recommend you not to update to the latest versions.
Therefore please navigate to the link below where we provide downloads for the latest versions of our software that should still work with your device.
https://help.tobii.com/hc/en-us/articles/213546185-Attention-all-REX-users
Please let us know if we can be of any further assistance.