After a Windows update Outlook will not start. It shows "Your Outlook data file cannot be configured" and then closes. I have Outlook 2019. My emails are in a PST file on the D drive. Is the file damaged?

The file is usually fine. This error normally points to a broken Outlook profile or a permission problem on the file, not to damaged data.

Try these in order:

1. Make sure the PST is not read-only. Right click it, select Properties and clear the Read-only box.
2. Make sure it is not inside a synced OneDrive folder. Move it to a normal local folder.
3. Create a fresh profile. Control Panel > Mail > Show Profiles > Add. Set up your account, then go to Data Files and add your old PST as a data file.

A new profile fixes this in most cases because the old profile entry for the PST is what became inconsistent.

Read-only was ticked. Unticked it and the error is gone. Strange that an update did that.

Updates sometimes reset the attributes when a drive is remapped. Good that it was that simple. If you ever see the error again, go straight to the new profile step and keep a copy of the PST first.