Installation of Qt takes a long time, there's lots to download and install.

At somepoint the installer on Windows needs to get authorization from Windows to make changes. Given how long it takes it's quite likely that the workstation is no being attended to, got up for coffee, gone to lunch, whatever, and the authorization request times out. There's a nice popup that says what to do but it includes a very long alpha-numeric string (--startserver PRODUCTION,{0d53bfe9-a4ee-4d1d-b0dd-928a0672bac0},(229b448f-b51d-42f8-8aec-621ce0f2b8a}) that needs to be entered. It is not possible to copy/paste that from the dialog so horribly user unfriendly.

So why not have a "retry" dialog and do it for the user?

Or think of some other solution to get around this problem.