macOS Golden Gate 27.0.1 mackbook doesn’t let me see notification centre or add widgets

Try restarting your MacBook Air (M4, 2025) first. 

Save your work, click the Apple menu , and select Restart. Once your Mac starts up again, check whether the following features work.

Click the date and time at the top-right of the screen to open Notification Centre. 

If nothing happens, try swiping left with two fingers from the right edge of the trackpad. For more information, see Apple’s Notification Centre guide.

To add widgets, Control-click an empty area of your desktop and select Edit Widgets. 

If Notification Centre opens, you can also click Edit Widgets at the bottom. See Apple’s guide to adding widgets.

For the Dock options, Control-click or right-click an app icon. 

Double-clicking normally opens the app rather than showing its options.

If these features still do not work, check System Settings >> Trackpad for gesture settings and System Settings >> General >> Software Update for available updates. 

An update may be worth checking, but it is not  necessarily the cause.

To help avoid a lengthy back-and-forth, you can optionally download EtreCheckPro directly from its developer. 

Run it to generate a report that may help with diagnosis. 

Download the Application Etrecheck  ( External Link ) directly from the Developer.

This is a Diagnostic Tool that makes no changes to the computer.

It makes a coherent and readable inventory of both the Hardware and Software used on the computer 

The application is free or paid for added features. 

The Report will Not Reveal Any Personal Information. 

Post back the Full Report - Share Report >> Copy , then  paste  >>>> using the Additional Text Icon  <<<<

If another user account already exists on your Mac, you can optionally test whether the same problems occur there. 

There is no need to create a new account just for this test.

If you are still stuck, contact Apple Support and explain which features aren’t working and what you’ve tried. You can also share your EtreCheck report after reviewing it.

It looks like the system processes managing your user interface elements (like the Notification Center, Widgets, and the Dock) have temporarily crashed or hung. This can prevent gestures, clicks, and context menus from reacting properly.

You can fix this by force-restarting the background services using the Terminal app.

Force Restart the Interface Services

• Open Spotlight Search by pressing Command (⌘) + Spacebar on your keyboard.
• Type Terminal and press return.
• Copy and paste the following command exactly as it appears into the Terminal window, then press return:

killall NotificationCenter ControlCenter Dock SystemUIServer

(Don't worry if your screen flashes or the Dock disappears for a brief second—macOS is automatically relaunching these core background tasks fresh).

More info from Apple: Use Notification Center on Mac - Apple Support

If that does not work, then see if the problem is present when you boot in safe mode. That process performs some system cleanup and clears caches, and also disables 3rd party extensions that may cause problems.

Start up your Mac in safe mode - Apple Support

If that does not correct the issue, test in a new user account. A newly-created user account will have all settings at default, and if the issue does not occur in that new account then it provides guidance on what may need to be changed to correct the issue.

Add a user or group on Mac - Apple Support

Once the testing is complete, the new account can easily be deleted.

Delete a user or group on Mac – Apple Support

Those steps will help to isolate the problem.

You mention "double click an app from the dock", that is not a supported behavior on macOS. To launch an app from the Dock, click on it ONCE. If you want to see the options for that app, then you need to secondary-click (right click, control-click) on the app in the Dock. For example, the Mail app after a secondary-click on the app in the Dock:

More info from Apple: Use the Dock on Mac - Apple Support