A description of nrf Connect states that it comes with apps. Do you have a limited demo version? Or a fully operational licensed version?
When installing a software package, it's a good idea to make everything easy for the installer.
* Go with default options.
* Disconnect from network.
* Turn off tasks that could interrupt the install. This includes a dozen things and if we forget a few then we have to hope luck is on our side.
* Restart your computer afterward.