Make broken Start menu and Cortana to function again. Getting closer to the launch date of Windows 10, but still the preview builds at present aren’t stable enough for daily use. Start menu and Cortana doesn’t open. If you’re experiencing this issue in Windows 10 insider Preview builds, try the following solution, it worked for me.

READ: PCs that Cannot Run Windows 10 will see Upgrade icon After July 29, 2015

Fix: Start Menu and Cortana doesn’t work in Windows 10

1. Open run command, type PowerShell and press enter to open it

2. Right click on its icon on taskbar and select Run as administrator

3. Paste the below script

Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}

4. Wait for the Powershell to complete the process, ignore any errors if displayed in the window.

running script in Windows Powershell

ALSO SEE:Windows 10 build  Default Apps Issue: How to set Chrome as default browser?

5. Once Powershell completes the process, click on the start button, start menu opens and cortana also works.

UPDATE August 04, 2015: If you’re getting the error: ‘Crucial error: Start Menu and Cortana aren’t working’, I can confirm this: Microsoft is aware of this issue and is working on a fix, software gaint hasn’t mentioned when it will be available. We’ll let you know when the fix is available.

From my side, I suggest you to try the above fix, if that doesn’t work, try to reset by going to Settings > Update & Security > Recovery (before doing this ensure your sytem is activated, that’t the key), or wait till MSFT offers the solution to this.

UPDATE August 26, 2015: Microsoft suggests temporary workaround for this error, you need to enter into Safe mode and then getting back to normal mode fixes the issue, but the error may return later.

CHECK: Temporary fix for Start menu and Cortana’s critical error

UPDATE October 1, 2015: Microsoft has released a cumulative update Kb3093266 to address critical error dialogs, check this, install the update and check if the issue persists.