We released a new Preview of Quality Rollup for the .NET Framework.

Preview of Quality Rollup releases are recommended for businesses that want to use and/or preview quality improvements as soon as they become available. These same quality improvements will typically be included in the following Security and Quality Rollup.

Quality and Reliability

This release contains the following quality and reliability improvements.


  • Dynamic method compilation may fail due to out of memory if memory for the code is not available near its precode [394998, 394999]
  • Memory leak in AppDomain::m_clsidHashMap growing [431586]
  • EETypeHashTable lookups can deadlock with GC during comparison with unrestored persisted TypeHandles [435005, 435006]


  • Performance improvements in Entity Framework [445511]
  • System.Data.SqlClient: Errors due to undersized prelogin packet data buffer [445492]
  • Handle leak with SqlConnection object [440114, 440116]


  • Reboot method of Win32_OperatingSystem has Privilege not held exception [441902, 441903, 441904]

Windows Forms

  • MdiWindowListItem remove MDI from list after closing cancellation [396476]


  • Use after free/double free in PenIMC [429048]
  • NullReferenceException thrown from PresentationFramework.dll during SpellCheck operations after SpellCheck.CustomDictionaries.Clear() is called programmatically [432174]
  • Crash caused by HEAP_CORRUPTION_ACTIONABLE_BlockNotBusy_DOUBLE_FREE_c0000374_PenIMC.dll!CPimcTablet::ReleaseCursorIn fo [429047]
  • Crash caused by INVALID_POINTER_WRITE_c0000005_PenIMC.dll!CPimcContext::GetPenEventMultiple [429046]


  • Incorrect Validation logic is applied when handling the <xsd:whiteSpace value=”collapse”/> directive in System.Xml [227903, 440921, 440932]

Getting the Update

The Security and Quality Rollup is available via Windows Update, Windows Server Update Services and Microsoft Update Catalog.

This release will only be offered on Windows Update on machines that have either .NET Framework 4.7 or the May 2017 Preview of Quality Rollup installed. You can still acquire the updates for a broader set of machines from the Microsoft Update Catalog. This set of changes will be made available on Windows Update to the broader set of Windows versions in August 2017.

Docker Images

Docker images have not been updated for this release.

Downloading KBs from Microsoft Update Catalog

You can download patches from the table below. See .NET Framework Monthly Rollups Explained for an explanation on how to use this table to download patches from Microsoft Update Catalog.

Product Version Preview of Quality Rollup KB
Windows 10 Update 1607 (Anniversary Update)
Windows Server 2016
.NET Framework 4.6.2, 4.7 4025334
Windows 8.1
Windows RT 8.1
Windows Server 2012 R2
.NET Framework 3.5 (reship of May release) 4014598
.NET Framework 4.5.2 4024843
.NET Framework 4.6, 4.6.1, 4.6.2, and 4.7 4024847
Windows Server 2012 Catalog
.NET Framework 3.5 (reship of May release) 4014594
.NET Framework 4.5.2 4024844
.NET Framework 4.6, 4.6.1, 4.6.2, and 4.7 4024846
Windows 7
Windows Server 2008 R2
.NET Framework 3.5.1 4014596
.NET Framework 4.5.2 4024845
.NET Framework 4.6, 4.6.1, 4.6.2, 4.7 4024848
Windows Server 2008 Catalog
.NET Framework 2.0 (reship of May release) 4014592
.NET Framework 4.5.2 4024845
.NET Framework 4.6 4024848

Source: .NET Framework July 2017 Preview of Quality Rollup | .NET Blog