Hotfix rollup 3146718 (web installer) for the .NET Framework 4.5, 4.5.1, and 4.5.2 in Windows

Applies to: .NET Framework 4.5Windows 8.1Windows RT 8.1

This article describes hotfix rollup 3146718, which is available for the Microsoft .NET Framework 4.5.2, 4.5.1, and 4.5. For more information about the issues that the hotfix rollup fixes, see the "Issues that this hotfix rollup fixes" section.

The Web Installer is a small package (smaller than 1 MB) that automatically determines and downloads only the components that are applicable to a particular platform. 


The following files are available for download from the Microsoft Download Center:

Download Download the web installer 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
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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 3146711 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 have to 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.
Performance optimization has been added to this scenario. If page settings are not modified for a specific page, printer settings are not reapplied (by accessing to the printer spooler) for this page. If the application modifies printer settings by using the QueryPageSettings event handler, print preview generation performance for the affected pages will not improve 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 .NET Framework

.NET Framework 4.5.2:

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

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

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

ClickOnce issue

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

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