sharepoint server 2019 command bar and items grid broken after CU September 2020 (Only Italian Language)

Question

I installed the CU September 2020 (KB4484504 and KB4484505). After that, the command bar on libraries and lists and in the items grid are broken.

I created a new site in English language and there the command bar is visible. Is there any solution?

Answer 1

This is a bug introduced with this CU. Looks like this only happens to localized webs. It is already listed as known issue: https://support.microsoft.com/en-us/help/4484505/security-update-for-sharepoint-server-2019-sept-8-2020

Workaround is to use classic mode at the moment.

As far as I heard, there are already some cases open for this behavior.

Answer 2

I just posted about the august cu breaking oob menu functionality in SharePoint 2019.In the console I see js errors introduced after the updates. Checkout your chrome dev tools console and i bet you will see some awesome new errors courtesy of microsoft.

Answer 3

Install KB 4484504. See the following documentation. This helped me resolve the missing command bar. https://support.microsoft.com/en-us/help/4461512/september-21-2020-update-for-sharepoint-server-2019-kb4461512