Fix: The .NET Framework 4.7 is not supported on this operating system If the issue is with your Computer or a Laptop you should try using Restoro which can scan the repositories and replace corrupt and missing files.
How to Install .NET Framework 3.5 on Windows Server and Apr 22, 2020 How to Install .NET Framework 3.5 within Windows 8 or 8.1 Feb 20, 2019
Downloads for building and running applications with .NET Framework. Get web installer, offline installer, and language pack downloads for .NET Framework.
".NET 4.5 is not installed." during installation of HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\1033; In the right pane, double-click Version for each key and make a note of it. Then change the corresponding value to 4.5. Note: If it is not possible to modify the registry key due to an Access denied error, follow these steps:
Method 1. Remove .NET FRAMEWORK 4.7 and then Install .NET FRAMEWORK 3.5. 1. Open Programs and Features and then click Turn Windows features on or off. 2. Uncheck the .NET Framework 4.7 checkbox and click OK to remove the latest installed version of NET FRAMEWORK. 3. When the removal process, enable the .NET Framework 3.5 and click OK.
Had it not been me figuring out the first problem and answering with the solution it likely would still be unanswered.. I don't know why they merged 2 topics with issues … Microsoft .NET Framework 4.8 Offline Installer download Apr 20, 2019 Install .NET Framework 3.5 in Windows 10 - Winaero