Fixed by another in-place upgrade to 25H2.

Hi Anon,

What you are experiencing is related to how Windows 11 differentiates between left and right Alt keys combined with the Alt+Tab interface and keyboard input handling. Normally, pressing Alt+Tab brings up a full window switcher showing all open apps, but in some cases, the system may only switch to the last used window if the left Alt key is not being recognized properly or if certain keyboard settings are interfering. The fact that the right Alt key partially works confirms that the issue is keyboard-specific rather than a global system problem.

To restore the normal all-window view, you can try several approaches. First, check your keyboard layout in Settings → Time & Language → Typing → Advanced keyboard settings to ensure it matches your physical keyboard. Second, confirm that sticky keys, filter keys, and other accessibility features are off, as these can alter Alt+Tab behavior. Third, try reinstalling or updating your keyboard driver via Device Manager, and if you are using a laptop with function key combinations, make sure no Fn lock or key remapping software is active. Additionally, some users have resolved similar issues by running Windows Terminal as administrator and executing sfc /scannow to repair system files that control window switching.

If none of these steps help, testing with an external keyboard can determine whether the left Alt key itself is malfunctioning. In most cases, the all-window Alt+Tab functionality returns once the system correctly recognizes the left Alt input or after updating the keyboard driver.

tldr; Long story short, a cable kept the ESC key pressed. I removed the cable, the ESC key got released, everything is fine now. I can ALT+TAB now without problems.

I managed to reproduce this behaviour: I had a heavy object (a cable) sitting on my keyboard at the time which was holding down the Esc key. The reboot didn't actually do anything, but I must have tugged on the cable at some point and moved it.

While the Esc key is held down, the Alt+Tab combination doesn't do anything. Perhaps this is to avoid conflicts with some other key combination involving Esc. As noted, Win+E still opens an Explorer window. Win+Tab does seem to work with only Esc held down, but not with the adjacent* § key held down instead so I guess the heavy cable might have moved while I was troubleshooting.

* I'm using a Swiss keyboard so this is the layout https://en.wikipedia.org/wiki/File:KB_Swiss.svg

Hello FantasticFox24，

Welcome to Microsoft Community.

Thank you for your detailed information. I would like to ask if Alt+Tab or pressing the Windows key does not respond, does pressing other keys respond? I reviewed the update log for KB5016688 and found no known issues with this update causing keyboard shortcuts to fail. I think we can start by looking at a few things.

First, please make sure that your computer and keyboard have the "Game mode" function. Some laptops (such as high performance gaming laptops) have a button that locks the system function key to prevent you from accidentally touching it while playing.

Then, click Search on the taskbar, type "Troubleshooter" and open it, click Run other Troubleshooter, select "Keyboard" and wait for the system to check to see if the keyboard works.

At last, we can check the function of Alt+Tab from the registry key.

1. You can open the registry editor by clicking Search on the taskbar, type regedit, navigate to the HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer path,
2. Create a DWORD value on the right, named it AltTabSettings, and value is 1.
3. Then restart your computer to see if the problem goes away.

Disclaimer: Generally, modifying registry subkeys or work group is intended for advanced users, administrators, and IT Professionals. It can help fix some problems, however, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For further protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click **** here to view the article.

Adding this key will force the Alt+Tab function to turn on, so you can test it. If there is any confusion or updates, please feel free to let me know.

Best Regards,

Manson - MSFT | Microsoft Community Support Specialist

It's apparent from reading the answers and trying each suggestion that for the most part, the reviewers are not familiar with the use of the Alt Tab. I typically have 16 apps open. In one time in ten I have to switch out of the pair I'm using. The other 9 out of 10, I'm switching back and forth between 2 apps. With Win10, I could use the Alt Tab switching rapidly between two apps recovering numbers, spelling or information to feed from one program into the other. Under Win11, one app now falls to the near bottom if not the absolute bottom of my open windows selection so I must Alt Tab 15 times to get to it all the while concentrating on NOT going past it, forgetting why I was switching back and forth and forcing me to repeat the process as much as 3 times or 45 keystrokes.
. There is a lot of bias against touch typers like me. And I feel this is one of them. Someone who doesn't keep his hands on the keyboard has made a decision to make us as slow as the mouse people.

Hello Song, welcome to the Microsoft community, I'll be happy to help you today;

I understand that the Alt key stopped working in Windows 11;

Initially I recommend that you try to disable the sticky keys;

Access the Control Panel;

Click Ease of Access;

Click Change how the keyboard works;

Disable "Enable Sticky Keys"

Click Apply;

Run the Troubleshooter for Keyboard;

Press Windows key + i and go to System;

Click on Troubleshooting and then on Other Troubleshooters;

Locate keyboard, and click run to start troubleshooting;

Finally do a clean boot;

Press together the keys: Ctrl + Shift + Esc to access the Task Manager;

Disable all programs that start with Windows;

Restart the PC and check the Alt key now works normally;

Hope this helps, see you soon!

Hi, Matthew,

Sorry to hear you're experiencing this issue.

As the Alt key is not detected even in the keyboard tester, is more likely that your laptop keyboard is physically damaged. The first thing that you can try is to use the on-screen keyboard or connect an external USB keyboard to your laptop and check if the Alt key works normally.

If the Alt key work normally using the on-screen keyboard or the USB keyboard, this indicates that is physical damage to the laptop keyboard. You will need to contact your laptop manufacturer's support to replace your laptop keyboard.