Diagnostic not working after latest software update

<< Before it's automatically started diagnosis. But now, it's not. >>

In macOS Tahoe 26 and later, you’re asked to choose a specific diagnostic to run, such as a diagnostic for your built-in display, keyboard, or trackpad. In earlier versions of macOS, this is automatic.

as the article that HWTech posted says, the diagnostic under MacOS 26 does not start automatically.

How or when is it not working? Any error messages?

Here is an Apple article with instructions for accessing the Apple Diagnostics (the steps for the M-series Macs has changed from the Intel Macs):

Use Apple Diagnostics to test your Mac - Apple Support

Also, you may want to review the following article which has tips for asking for assistance online:

Writing an effective Apple Support Communities Question - Apple Community

borhandipto wrote:

Model- MACBOOK PRO M3 PRO

Error massage: Diagnose

identify potential hardware or software issues of this Mac.

Please post a picture since I'm not sure where you are seeing that message.

Was this while trying to run one of the diagnostic tests or was this while booting into the diagnostic interface?

Tomorrow I will put one of the laptops where I installed Tahoe for testing into the Apple Diagnostics to refresh my memory of exactly how it works at each step of the way.

Edit:

It's not work like before.

Before it's automatically started diagnosis. But now, it's not.

On the older versions it was possible to use the keyboard to get to each screen, but with M-series Macs & later versions of macOS, it has become very annoying that some things cannot utilize the keyboard & requires clicking options with a mouse/trackpad.

I'm sure there are there are others— a quick google search in Youtube this was the first thing to popup

see if there is any insight:

A look at the new diagnostics menu in macOS Tahoe

https://www.youtube.com/watch?v=4qgtMc8pPsU

That does not look like an error message to me.

That looks like an ACTION you could choose.

I think it may be waiting for your input.