Windows 10 Anniversary update: Search bar doesn't work after update

I'm not sure if Cortana is installed your system or not. But I'm certainly sure that Cortana is a MAIN part of Windows Search, and in SOME of Windows 10 editions Cortana is Disabled by default. Meaning it's installed on the system, but its functionality is DISABLED. If something happened to Cortana files, then the WHOLE search system will be affected as well. Same thing happens in reverse.

So, what you actually need to do, is to reinstall Cortana from the Local Machine and not from the current user. The link that @Dave gave you is a one step but it will give an error (AS you experienced). Anyhow, I will give you the steps that I did in order to solve this issue.

1. Go to Services and disable + Stop Windows Search. (Then Save your settings).
2. Go to Powershell (Right-Click and open as administrator).
3. Type Set-ExecutionPolicy Unrestricted then hit enter.
4. Next, Type Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
5. Now, go back to Services and re-enable Windows Search, Change Startup to (Automatically Delayed Start) and click on Start.
6. Restart your system.

If you still experience problems, (press windows key + R) then type wsreset.exe, and follow the wizard. This should reset Windows Store cache (Yes, Windows Store affects all Windows built-in apps including Start menu functionality).

Method 2:

Open the command prompt as administrator, then Type:

DISM.exe /Online /Cleanup-image /Scanhealth

then hit enter.

Wait until it's finished then type:

DISM.exe /Online /Cleanup-image /Restorehealth

then hit enter. Wait until it's finished.

After it's done, go to Services and check Windows Search service, it should be Started / Automatic (Delayed Start)

Restart your system and check.

Method 3 (Best Answer):

• Download Tweaking.com's Repair Tool (Download the portable version)

After the file is downloaded, Uncompress it then run Repair_Windows.exe as administrator to avoid any permission issues. Then follow the following steps:

From Tweaking.com's Repair Tool window do the following:

• Go to Repairs tab
• Click on Open Repairs
• Untick first option (parent option) to untick all its options.
• Now, tick the following options:
  • 27 Set Windows Services To Default Startup
  • 28.02 Repair Windows 8/10 App Store (Completely Reset App Store)
• Then, click Start Repairs, and the tool will do the rest of the work.

When it's done, make sure to restart your machine.