Practical Commands (concise)

To ensure a successful installation on Server 2012 R2, follow this proven workflow: Place the File : Copy your downloaded microsoft-windows-netfx3-ondemand-package.cab to a local folder (e.g., C:\dotnet35 Run with Elevation : Open a Command Prompt or PowerShell as an Administrator Execute DISM

| Error | Cause | Solution | |-------|-------|----------| | 0x800f081f | Source files not found | Ensure CAB path is correct. Use DISM /Get-Packages to check if already partially installed. | | 0x800f0906 | Cannot download from Windows Update | Use DISM with /LimitAccess and /Source explicitly. | | 0x800f0922 | Disk space or corrupted image | Run DISM /RestoreHealth first, then retry. | | DISM fails with 0x800f0950 | Wrong CAB architecture (32-bit on 64-bit OS) | Verify you have the amd64 version of the CAB for Server 2012 R2 x64. |

The required file is: microsoft-windows-netfx3-onDemand-package.cab

Install-WindowsFeature Net-Framework-Core -Source D:\sources\sxs Using Server Manager (GUI) Server Manager Add roles and features Proceed to .NET Framework 3.5 Features Confirmation page, click Specify an alternate source path at the bottom. Enter the path to the folder (e.g., D:\sources\sxs Microsoft Learn Common Troubleshooting Error 0x800F0906 / 0x800F081F: