Garmin Express user name and password constant sign on when synching with Forerunner with 735XT

For some reason, since I updated to v7.0.0.0 I'm always prompted to enter my User Name and Password when opening up Garmin Express to synchronise my Forerunner 735XT. I enter it but it just goes back to the same dialogue box. When I cancel this I find I can then synch as normal, but it always wants to install my details first.

It isn't preventing me synching, but it is just annoying. I'm using an up to date Windows Dell laptop.