.NET Framework October 2020 Cumulative Update Preview Update

Tara Overfield

Yesterday, we are releasing the October 2020 Cumulative Update Preview Updates for .NET Framework.

Quality and Reliability

This release contains the following quality and reliability improvements.

  • Addressed an issue in System.Data.SqlClient where querying string columns would fail if the database had a Kazakh collation.
  • Addressed a regression from a previous update, arising when two HostVisual elements disconnect at the same time.
  • Addressed a crash and/or hang when typing into a TextBox in a WPF app, when the OS feature “use text cursor indicator” is enabled.

1 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. For Windows 10, NET Framework 4.8 updates are available via Windows Update and Microsoft Update Catalog. Updates for other versions of .NET Framework are part of the Windows 10 Monthly Cumulative Update.

**Note**: Customers that rely on Windows Update 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 and Windows Server, version 1909
.NET Framework 3.5, 4.8 Catalog 4580980
Windows 10 1903 and Windows Server, version 1903
.NET Framework 3.5, 4.8 Catalog 4580980
Windows 10 1809 (October 2018 Update) and Windows Server 2019 4581000
.NET Framework 3.5, 4.7.2 Catalog 4580422
.NET Framework 3.5, 4.8 Catalog 4580979


Previous Cumulative Updates

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


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

  • Junaid SH 0

    Thanks for the best Article. really appreciate the efforts. i surely this with my partners. After seeing your article I want to say that also a well-written article with some very good information which is very useful for the readers. the article on .NET Framework is very useful content for developers

  • Dean Jackson 0

    Please explain these “Preview” updates. Some years ago, the “Preview” update was released a month ahead of the “real” update, which would come the next month. The preview was considered optional, and the real one required.
    Is this the same, or does Windows 10 list this as required, even though “preview” is in the name ??

  • John Kerry 0

    Thanks for the information and the one above 30-10-2020. A number of the Preview Updates are automatically installing themselves on 19041.574 plus again yesterday, automatically, on 19041.602 and on Enterprise builds too.

    Why are the Preview Updates installing themselves automatically ?

    I would prefer that they didn’t and obeyed the rules that updates similar to 20H2 follow, in that Users are presented with these as “optional downloads” and only installed after specifically opting in to receive them each time.


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