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Hotfix rollup 3146709 for the .NET Framework 4.5, 4.5.1, and 4.5.2 in Windows

This article describes hotfix rollup 3146709, which is available for the Microsoft .NET Framework 4.5.2, 4.5.1, and 4.5. For more information about the issues that this rollup fixes, see the "Issues that this hotfix rollup fixes" section.
The following files are available for download from the Microsoft Download Center:

DownloadDownload the x86 package now.

DownloadDownload the x64 package now.

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to obtain Microsoft support files from online services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

Note To verify the hotfix update version, check the value of the Release keyword to determine the installed version. To be forward-compatible, you can check for a value that's greater than or equal to the value that's listed in the following table.

Hotfix Rollup Version Value of the Release DWORD
Hotfix rollup 3146709 for the .NET Framework 4.5 and later versions 380035
For more information about how to determine the .NET Framework versions, see How to: Determine which .NET Framework versions are installed.
More information


To apply this hotfix, you must have the .NET Framework 4.5.2, 4.5.1, or 4.5 installed.

Restart requirement

You must restart the computer after you apply this hotfix if any affected files are being used. We recommend that you close all .NET Framework-based applications before you apply this hotfix.

Hotfix replacement information

This hotfix package doesn't replace a previously released hotfix package.

Issues that this hotfix rollup fixes

ASP.NET issue

Contention and bad performance on System.Web.BufferAllocator when you run a web application on computers that have more than 32 cores.

Fix: The contention has been eliminated by removing the global lock in System.Web.BufferAllocator.​

Windows Forms issue

The Windows Forms PrintPreviewDialog UI is initialized very slowly when the following conditions are true:
  • A network printer is used.
  • User preferences for this printer, such as duplex settings, are modified.
We added a performance optimization to this scenario. If page settings are not modified for a specific page, printer settings for this page are not reapplied (by accessing the printer spooler). If the application modifies printer settings by using the QueryPageSettings event handler, print preview generation performance for the affected pages is not improved, even if the opt-in flag is set.

In order to opt in to this optimization, the following key should be added to the app.config file, depending on your version of the .NET Framework.

NET Framework 4.5.2:

<?xml version="1.0" encoding="utf-8"?><configuration>   < appSettings >       < add key="OptimizePrintPreview" value="true" />   < /appSettings ></configuration>
.NET Framework 4.6 or a later version:

<?xml version="1.0" encoding="utf-8"?><configuration> < runtime>   < AppContextSwitchOverrides value = "Switch.System.Drawing.Printing.OptimizePrintPreview=true" /> < /runtime></configuration>
If an application can run on either version of the .NET Framework, use both switches in the same file.

To opt out, remove the switch, or set the values to false. ​

ClickOnce issue

ClickOnce has been updated to support TLS 1.1 and 1.2. ClickOnce automatically detects which TLS protocol is required at runtime. There are no extra steps required in the ClickOnce application to enable this.

Note ClickOnce continues to support TLS 1.0 for the foreseeable future, even though it is no longer considered PCI-compliant.​

Article ID: 3146709 - Last Review: 04/13/2016 18:38:00 - Revision: 1.0

Microsoft .NET Framework 4.5.2, Microsoft .NET Framework 4.5.1, Microsoft .NET Framework 4.5, Windows 8.1, Windows RT 8.1, Windows Server 2012 R2 Standard

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