.NET Framework October 2020 Cumulative Update Preview for Windows 10 2004 and Windows Server, version 2004

Tara Overfield


Yesterday, we released the October 2020 Cumulative Update Preview 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 VersionCumulative Update
Windows 10 2004 and Windows Server, version 2004
.NET Framework 3.5, 4.8Catalog4580419


Previous Cumulative Updates

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


Leave a comment

  • Avatar
    Rich K

    Please allow me to offer a little constructive criticism of the wording used in this post and some of the previous ones. Two things caught my attention.
    First, the opening boilerplate – “Yesterday, we are releasing …” This ought to be “Yesterday, we released …”
    My second point is one I’m less sure of. I’m confused by the phrase in the title (and throughout the post) “… Cumulative Update Preview Update …” After reading the post, my impression is that you are announcing a new cumulative update for .Net 3.5 and 4.8 software. I’m not sure what the word Preview and the second use of Update mean in this context. I know that some Microsoft software products are “Preview Editions”, but I do not think this is the case here (I could be wrong). More likely Preview and/or Update might have been meant as a description of the Blog Post itself – i.e. “Preview of … Update”, or “Update on the … Update”. If so, then one of the formulations I just used might have been more clear. But of course, if you’re describing something that was released ‘yesterday’, calling it a Preview would probably be incorrect.
    Assuming I’ve interpreted things correctly, I’d suggest a title something along the lines of “Announcing .NET Framework October 2020 Cumulative Update for Windows 10 2004 and Windows Server, version 2004”. Or “Summary of …”, etc.
    As someone who’s written my share of technical documentation I empathize with the tedium involved. But as a consumer of technical documentation, I also appreciate it when it’s clear, concise, accurate and complete. Well written documentation can save a developer much time, and poorly written documentation can waste it.
    Keep up the good work. Thanks

    • Avatar
      Ismail Demir

      she copy-pasted most of the sentences from the previous update. “today” was edited to “yesterday” without correct the whole sentence, and maybe the title too (IMHO, “Cumulative Update” should be removed) – happened 🙂

      And yes as non english speaker I had to read it twice. ^_^

    • Avatar
      Ray Bloom

      I, too, am curious as to the use of the term “Preview“. But the use of “Preview” is not part of the blog post, per se, but is actually in the title of some of the recent updates.

      For example, in Windows Update, this particular update appears as “2020-10 Cumulative Update Preview for .NET Framework 3.5 and 4.8 for Windows 10 Version 2004 for x64 (KB4580419)”. Last month, Windows Update installed “2020-09 Cumulative Update Preview for .NET Framework 3.5 and 4.8 for Windows 10, version 2004 for x64 (KB4576945)”, and it’s listed under “Other Updates” rather than the usual “Quality Updates” category. (There was also a regular 2020-09 .NET cumulative update which does appear under “Quality Updates”.

      I would very much like to know why Preview updates are being installed by default. If they are, indeed previews, then it seems to me that they should by optional updates.

      Can you clear this up for me, Tara?