After no results online, I began experimenting with this issue. Apparently, after the password prompt and the software is minimized, you can click on Quickbooks in the Taskbar and open Full Screen again. However the issue kept repeating. To get around this issue, I opened Quickbooks again and then I simply chose the "Restore Down" button (2 squares overlapping each other) which is in between the minimized button and the X button in the upper right corner. Closed Quickbooks and then re-opened, the software was now at half screen vs. the Task Bar.  I then dragged the corners of Quickbooks software and stretched to liking, closed out of Quickbooks and this seemed to solve the issue. No solutions in Preferences / Desktop View within Quickbooks or elsewhere online. Hope this solution helps someone.