.NET Framework June 27, 2019 Cumulative Update for Windows 10 version 1903

Brett Lopez

Today, we released the June 2019 Cumulative Update for .NET Framework 3.5 and 4.8 on Windows 10 version 1903.

Quality and Reliability

This release contains the following quality and reliability improvements.

  • Improves the memory allocation and cleanup scheduling behavior of the weak-event pattern. To opt-in to these improvements, set AppContext switches to “true”: Switch.MS.Internal.EnableWeakEventMemoryImprovements and Switch.MS.Internal.EnableCleanupSchedulingImprovements.
  • Addresses an InvalidOperationException that can occur during weak-event cleanup, if called re-entrantly while a weak-event delivery is in progress.
  • Addresses InvalidOperationException errors in System.Web.Hosting.RecycleLimitMonitor+RecycleLimitMonitorSingleton.AlertProxyMonitors. Worker processes for ASP.Net 4.7 and later are vulnerable to unexpected crashes because of this exception if the worker process consumes close to its configured Private Bytes recycling limit and application domains are being created or recycled (perhaps because of config uration file changes, or the presence of more than one application per worker process).
  • Addresses an issue in which it was possible for a Workflow Service to get into a looping situation if an unhandled exception occurs during Cancel processing. To break this cycle, the Web.config file for the workflow service can have the following AppSetting specified that will cause the workflow service instance to terminate, instead of abort, if an unhandled exception occurs during Cancel processing:<appSettings> <add key=”microsoft:WorkflowServices:TerminateOnUnhandledExceptionDuringCancel” value=”true”/> </appSettings>
  • Addresses multiple Accessibility and High DPI awareness improvements for Windows Forms and Windows Presentation Foundation (WPF) applications.

Getting the Update

The Cumulative Update is available via Windows Update, Windows Server Update Services (WSUS) and Microsoft Update Catalog.

Microsoft Update Catalog

You can get the update via the Microsoft Update Catalog.

Product Version Cumulative Update
Windows 10 1903 (May 2019 Update) .NET Framework 3.5, 4.8 Catalog 4502584

Previous Monthly Rollups

The last .NET Framework update for Windows 10 version 1903 is listed below for your convenience:


Discussion is closed. Login to edit/delete existing comments.

  • Eaton 0

    Do you guys still monitor dotnet issues? There never seems to be much engagement regarding possible reported bugs. https://github.com/microsoft/dotnet/issues/1015

  • Paul Suurs 0

    Yesterday evening downloaded the update and during the install he restarted the computer.  My screen keeps totally black and a round cirkel keeps going on. What am I going to do now?

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