Microsoft .NET Framework 3.5.1
This update for Windows 7 Service Pack 1 (SP1) and Server 2008 R2 Service Pack 1 (SP1) includes cumulative reliability improvements in .NET Framework 3.5.1. We recommend that you apply this update as part of your regular maintenance routines. Before you install this update, see the Prerequisites and Restart requirement sections.
- If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.
Quality and reliability improvements
1 Common Language Runtime (CLR)
Additional information about this update
For more information about this update as it relates to Windows 7 SP1 and Windows Server 2008 R2 SP1, see the following article in the Microsoft Knowledge Base:
4489486 March 2019 Update for .NET Framework 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, and 4.7.2 for Windows 7 SP1 and Server 2008 R2 SP1 (KB 4489486)
Microsoft is not currently aware of any issues with this update.
How to obtain and install the update
Microsoft Update Catalog
To get the standalone package for this update, go to the Microsoft Update Catalog.
Windows Software Update Services (WSUS)
On your WSUS server, follow these steps:
- Select Start, select Administrative Tools, and then select Microsoft Windows Server Update Services 3.0.
- Expand ComputerName, and then select Action.
- Select Import Updates.
- WSUS opens a browser window in which you may be prompted to install an ActiveX control. You must install the ActiveX control to continue.
- After the ActiveX control is installed, you see the Microsoft Update Catalog screen. Type 4489486 in the Search box, and then select Search
- Locate the .NET Framework packages that match the operating systems, languages, and processors in your environment. Select Add to add them to your basket.
- After you select all the packages that you require, select View Basket.
- To import the packages to your WSUS server, select Import.
- After the packages are imported, select Close to return to WSUS.
The updates are now available for installation through WSUS.
To apply this update, you must have .NET Framework 3.5.1 installed.
You must restart the computer after you apply this update if any affected files are being used. We recommend that you exit all .NET Framework-based applications before you apply this update.
Update replacement information
This update does not replace a previously released update.
Windows 7 and Windows Server 2008 R2
The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed in the "Additional file information" section. MUM, MANIFEST, and the associated security catalog (.cat) files, are very important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
Additional file information