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Found it (at least for my freshly installed Windows 10 on a 64bit laptop). You need to have administrator rights and enable hidden files view. See https://www.wintips.org/how-to-access-windowsapps-folder-windows-10-8/ This did the trick: Part 1.How to gain Read Only Access rights to 'C:\Program Files\WindowsApps' folder. After this the installation of Nitro Pro 11 worked. didn't need Part 2. How to gain Full Access rights to 'C:\Program Files\WindowsApps' folder using the command prompt. Good luck

That seems extreme for trying to renew a subscription, but if that's my only choice....