Run Command Prompt or PowerShell .
This is the most common error. It means the DISM command cannot locate the microsoft-windows-netfx3-ondemand-package.cab file. Run Command Prompt or PowerShell
Go to the official Microsoft Download Center and search for "Microsoft .NET Framework 3.5." Download the full package (approx. 231 MB). Run Command Prompt or PowerShell
DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:D:\sources\sxs : Targets the operating system currently running. /LimitAccess : Prevents DISM from contacting Windows Update. Run Command Prompt or PowerShell