September 2020 CU for SharePoint Server 2019 is available for download

The product group released the September 2020 Cumulative Update for SharePoint Server 2019 product family. SharePoint Server 2019 is patched with a language dependent and a language independent fix.

The KB article for September 2020 CU will be available at the following Location in a couple of hours:

  • KB 4484505 – September 2020 Update for SharePoint Server 2019 (language independent) – This is also a security update!
  • KB 4484504 – September 2020 Update for SharePoint Server 2019 (language dependent) – This is also a security update!

The download for September 2020 CU is available through the following link:

Important: It is required to install both fixes (language dependent and independent) to fully patch a SharePoint server. This applies also to servers which do not have language packs installed. The reason is that each SharePoint installation includes a language dependent component together with a language independent component. If additional language packs are added later (only) the language dependent fix has to be applied again.

It is irrelevant which language you pick on the drop down in download center. Even the language dependent fixes are all in the same package for all languages.

After installing the fixes you need to run the SharePoint 2019 Products Configuration Wizard on each machine in the farm. If you prefer to run the command line version psconfig.exe ensure to have a look here for the correct options.

Please ensure to have a look at the SharePoint Patching Best Practices before applying new fixes.

SharePoint 2019 September 2020 CU Build Number:

Language independent fix: 16.0.10366.12106
Language dependent fix: 16.0.10366.12106

Related Links:

17 Comments


  1. Hello Stefan. I installed these CUs and I found this error: When I’m in a site with language Italian in the command bar modern document library is not loaded. I can not add new columns directly from the voice network. I can not change the grid view. If I change the language from Italian to English normally loads the command bar.
    What have I done wrong?

    Reply

    1. Hi Jonata,
      I would recommend to open a ticket with Microsoft Support to get this analyzed.
      Cheers,
      Stefan

      Reply

    2. Hi Stefan,
      I see the same issue as Janata and Teo with a german language pack and browser language set to german. Classic works fine.
      Is it right that you are not able to repro that (if you are using LPs at all)?
      I am able to reproduce in my lab and my productive environment.
      Thanks,
      Andy

      Reply

        1. Thanks for your quick reply Stefan.
          I should read your posts more carefully. 😉
          Now I can lean back and wait for MS… 😀

          Reply

  2. Hi Stefan

    Since we applied this patch, we are unable to edit lists in modern view (classic works).
    The popup form is shown but is blank without any fields shown.

    This is logged in console:

    Uncaught Error: Unknown component ‘ms-client-form’
    at knockout.js?rev=9WO%2BKSaWlwKiXini50jovg%3D%3DTAG0:6
    at knockout.js?rev=9WO%2BKSaWlwKiXini50jovg%3D%3DTAG0:6
    at e (knockout.js?rev=9WO%2BKSaWlwKiXini50jovg%3D%3DTAG0:6)
    at MutationObserver.t (knockout.js?rev=9WO%2BKSaWlwKiXini50jovg%3D%3DTAG0:6)

    Reply

    1. Hi Teo,
      I would recommend to open a ticket with Microsoft Support to get this analyzed.
      Cheers,
      Stefan

      Reply

  3. Dear Mr. Goßner, firstly thank you for your great site. We always come by when a farm needs updates. This time though we have a problem with kb4484504 (localization package german). After having successfully deployed kb4484505 it is telling us that “There are no products affected by this package installed on this system.”
    thank you
    Gerald

    Reply

    1. Hi Gerald,
      4484505 does NOT include 4484404.
      To possible reasons for what you see:
      1) 4484504 has already been applied (maybe through some automated installation) – you can check this in control panel – programs – installed updates
      2) the windows installer cache is corrupted and the package cannot be associated with an installed product.

      If 2 is the case you will not be able to apply any future fixes for this component either and I would recommend to open a ticket with Microsoft to get this analyzed and resolved.
      Cheers,
      Stefan

      Reply

      1. sadly it looks like case 2… last language pack applied was 25th june.. the problem exists on both of our 2 farms (one is single-dev-farm and another with 2 wfe and 2 app).. thank you

        Reply

  4. I need to correct myself, somehow the new file of that package I downloaded today is working now. It has installed with returncode 0. thank you again.
    Gerald

    Reply

  5. Just a note for folks looking at this CU: we have experienced breaking changes with customer and internally managed environments (likely related to this CVE which is addressed as part of this CU: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1460).

    Specifically, if you have custom web parts or custom master pages, it will raise new security errors and you will need to register assemblies into SafeControls. We are also experiencing some issues with regards to master pages which do not have code, but now the application is warning about inline code blocks. We are currently working to resolve these issues and understand the root cause.

    Before you apply this CU in production, be sure to test it in a test environment if you are using custom web parts or custom master pages.

    Reply

    1. Hi Charlie,
      please open a ticket with Microsoft if you need assistance with this analysis or if you see breaking changes you are not able to resolve.
      Thanks,
      Stefan

      Reply

      1. Stefan, we resolved the issues already via updates to the web.config.

        Just leaving a note for folks applying this update into environments with custom master pages and web controls, be aware that you will likely need to update your SafeControls and PageParserPath (if you get an error with regards to unsafe code blocks in your custom master pages).

        Cheers!

        Reply

        1. Charlie, we had the exact same scenario in SharePoint 2016. Code blocks on the master page caused errors and we needed to add PageParserPath entries along with SafeControls to get around the issue.

          FWIW, if you can remove the code blocks and instead use a technique like code behind, you don’t need the new SafeControl or PageParserPath. It gave us a bit of performance boost as well.

          Reply

  6. Hi, has there been any reports of problems with search after this update? For some reason we can no longer crawl pages with friendly urls after this update.

    Reply

    1. Hi Trond,
      A similar issue was fixed in August CU – I’m not aware of a new issue in September CU.
      I would recommend to open a support case with Microsoft to get this analyzed.
      Cheers,
      Stefan

      Reply

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