Has the program has ever been installed using this computer? Whether onto the PC hard drive, a USB flash drive, or a portable hard disk? If so, it is necessary to uninstall it before starting a new installation. The flash drive and portable drives should not be connected during the uninstall.
These are the steps.
That's left of center, about 5th line from top. Then you will see Microsoft's plea for reassurance.
The MarpX Privacy line has disappeared. Click the X in the upper right corner to leave the above screen.
The next step is to download the app.