.NET Framework June 2021 Cumulative Update Preview

Tara Overfield

Today, we are releasing the June 2021 Cumulative Update Preview for .NET Framework for Windows 10, version 1809, Windows Server 2019, and Windows 10, version 1909.

Quality and Reliability

This release contains the following quality and reliability improvements.

  • Addresses a regression introduced in previous updates. We now honor WinTrust policy setting “Ignore timestamp revocation checks” setting when validating timestamps in ClickOnce manifests.
  • When the process is not under high memory pressure it tends to favor doing BGCs over doing full compacting GCs. This is usually desirable but if the app behavior changes dramatically, it could cause much of the fragmentation in older generations (ie, gen2 and LOH) to be unused. You can collect GC ETW events which tell you how much fragmentation there is in gen2 and LOH and verify if you are in this situation.
Windows Forms
  • Addresses an issue in Property Grid control to prevent incorrect data read in some scenarios in 64 bit processes.
  • Addresses an issue where System.Drawing double frees allocated memory when failing to get printer settings.
  • Addresses an issue affecting a DataGrid contained in an outer ScrollViewer.
  • Addresses a crash due to ElementNotAvailableException in a ListView with custom data-item automation peers.

1 Common Language Runtime (CLR)
2 Windows Presentation Foundation (WPF)

Getting the Update

The Cumulative Update Preview is available via Windows Update and Microsoft Update Catalog.

Microsoft Update Catalog

You can get the update via the Microsoft Update Catalog.

**Note**: Customers that rely on Windows Update and Windows Server Update Services will automatically receive the .NET Framework version-specific updates. Advanced system administrators can also take use of the below direct Microsoft Update Catalog download links to .NET Framework-specific updates. Before applying these updates, please ensure that you carefully review the .NET Framework version applicability, to ensure that you only install updates on systems where they apply.

The following table is for Windows 10 and Windows Server 2016+ versions.

Product Version Cumulative Update
Windows 10 1909
.NET Framework 3.5, 4.8 Catalog 5003539
Windows 10 1809 (October 2018 Update) and Windows Server 2019 5003857
.NET Framework 3.5, 4.7.2 Catalog 5003541
.NET Framework 3.5, 4.8 Catalog 5003538


Previous Monthly Rollups

The last few .NET Framework Monthly updates are listed below for your convenience:

1 comment

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  • Cristian Georgescu 0

    And why are you forcing this update preview on me?
    – I’m not on any preview or beta channel;
    – my list (and everybody’s list) of available updates says “Security intelligence etc.” and “2021-06 Cumulative Update Preview for .NET Framework 3.5 and 4.8”;
    – the only Download button would download and install both updates despite the fact that I don’t want the preview one;

    You very well know what I’m talking about, it happens on each and every .NET update preview, we’ve complaining for this behaviour for 2 years now, https://answers.microsoft.com/en-us/windows/forum/all/how-to-completely-avoid-preview-updates/ef6d8489-8bc2-4479-aa91-cf9f5f72632c.

    In a funny twist, under those 2 security intelligence and .NET preview updates, I have another preview update for 21H1 but this one is optional.
    Why, out of 2 update previews, only one is optional? How’s that the .NET update preview is not optional?

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