Or using DISM with the source switch:
Open the setting: . Select Enabled .
If you have another running Windows Server 2012 R2 machine that already has .NET 3.5 installed, you can copy the file from its WinSxS side-by-side store repository located at C:\Windows\WinSxS\ . Method 3: Downloading from Official Microsoft Repositories
"Specify settings for optional component installation" to "Contact Windows Update directly". Spiceworks Community exact registry settings to bypass WSUS for this installation, or do you need help mounting the ISO Or using DISM with the source switch: Open the setting:
The safest place to find the clean, original .cab file is on the Windows Server 2012 R2 installation ISO.
Method 2: Using the .CAB File Directly (Offline/Alternative)
| 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. | Use DISM /Get-Packages to check if already partially
DISM.exe /Online /Enable-Feature /FeatureName:NetFX3 /All /Source:C:\NetFx3 /LimitAccess Use code with caution. Copied to clipboard /Source : Points to the folder containing the .cab file.
Note: The /LimitAccess switch is critical. It prevents DISM from attempting to contact Windows Update online, forcing it to use your local CAB file exclusively. Option C: Using the Server Manager GUI
When you attempt to install .NET Framework 3.5 on Server 2012 R2 through the "Add Roles and Features Wizard," Windows tries to download the required components via Windows Update. If your server is disconnected from the internet, blocked by a firewall, or constrained by Group Policy, this download fails. many enterprises still rely on it
In the lifecycle of Windows Server 2012 R2, few administrative tasks have proven as persistently necessary—or as deceptively complex—as enabling the .NET Framework 3.5 (NetFX3). Many legacy applications, from SQL Server older versions to custom ERP systems, refuse to run without it. While Server 2012 R2 reached its end of mainstream support, many enterprises still rely on it, requiring administrators to source the elusive for a reliable, source-based installation.
Without a designated source path, installations via the Server Manager GUI or PowerShell will fail, usually accompanied by Error Code 0x800F0906 or 0x800F081F .
: Points to the sxs folder on your media where the .cab file is located.