: Use the official Microsoft Media Creation Tool (or the Windows 11 version) to download the ISO that matches your current Windows version.
Keep this CAB file on a USB stick. If you reformat your PC or get a new work laptop, you can install .NET 3.5 in seconds without an internet connection. Download Microsoft-windows-netfx3-ondemand-package.cab
If you’ve ever tried to install older software (like AutoCAD 2016, SQL Server 2014, or legacy ERP tools) on Windows 10 or Windows 11, you’ve likely encountered the dreaded error: : Use the official Microsoft Media Creation Tool