You aren't prompted for required information when you upload a file to a SharePoint Online library using the new experience version
Consider the following scenario:
You're using the new experience version for document libraries in SharePoint Online.
You have a column where the Require that this column contains information setting is set to Yes.
In this scenario, when you upload a file to the library, you're not prompted to enter a value for the required column. In addition, the file isn't checked out by default when you view it in the classic document library experience.
To resolve this issue, use the classic view for the affected library. For more information, see Switch the default experience for lists or document libraries from new or classic.
This issue occurs when you upload files to a SharePoint Online library that uses the new document library experience.
After you upload a file that's missing the required information, when you open the file in a Microsoft Office application, you may be prompted with one of the following messages:
REQUIRED PROPERTIES To save to the server, correct the invalid or missing required properties.
This file cannot be saved because some properties are missing or invalid.
In the Microsoft Office application message, click Edit Properties or Go to Document Properties. Then type a value for the required column so that you're able to save any changes.
Still need help? Go to SharePoint Community.