Broken search, possibly language related? Cortana incomplete results.

Yes, typical of a not quite complete language change. MS ought to make this wizard-based, it is so confusing, as you need to make several changes. It's a weakness.

You seem to have changed the obvious things. I seem to recall 2 additional downloads besides changing the display language, one for speech, which you've done. Thank you for the thorough set of screenshots.

You should see helpful tips when you click Learn More in Cortana (2nd screenshot) and the tabs shown. Have you worked through these?

What is the original language of your OS?

That's what you need to see.. mine was US originally, changed to UK

One thing that doesn't matter here is the keyboard/input language setting.

Have you tried setting up your microphone for speech recognition?

Frustrating it may be, but it is an area that requires patience to resolve. I struggled with this the first time I changed from US to UK English.

Have you tried setting up your microphone for speech recognition?
Please post a screenshot of Control Panel, Indexing Options.

Now one thing I have learnt in working with someone in another thread is this:
They noted that if they searched immediately after logon (as fast as possible) they got a search result. But immediately afterwards, they found that a search failed with the same error you are getting.

I found I could emulate that by disabling the Windows search service. Simply starting it again isn't enough - same error message. To have search working properly again required rebuilding the index. (And I did try restarting before deciding to rebuild it - restarting didn't help).

N.B. I'm not suggesting rebuilding the index will necessarily help- if your screenshot of it shows it's complete.

I'm wondering if you're seeing something similar - cause unknown.

Suggest you also try a clean boot.

Ok, the last thing to do is an in-place upgrade repair install. Functionally this keeps almost everything bar a few settings.

Here's my write-up:
Precede it with this in case sthg has happened to your file system:

From an admin command prompt
[Windows key + X, click command prompt (admin)]
chkdsk C: /F
Your PC will need to restart.
Make sure the result is clear or fixed- else do not proceed.
Post back the result, which you can get after a restart as follows:
How do I see the results of a CHKDSK that ran on boot? - Ask Leo!

An In-place upgrade repair install will fix many things, but not those where the settings are not changed by the procedure.

For this you need an installation medium with the same base build as you have installed, and x64 if you have a 64 bits OS, else x86 (32 bits).

Recommendation:
Before you perform the following major repair procedure, do create a disk image (see below).

Repair Install Windows 10 with an In-place Upgrade - Windows 10 Tutorials
- this includes a link from which you can obtain a Windows 10 iso file (" download a Windows 10 ISO"), or create a Win 10 bootable medium.

I would recommend creating the bootable medium, as this can be used
- for any future in-place upgrade repair install
- to boot from and use its recovery options should Windows become unbootable.
- to clean install Windows

This will refresh Windows, after the manner of a Windows installation.
- all/most associations will be unchanged
- all your programs will be left installed
- no personal data should be affected
- you will lose any custom fonts
- you will lose any customised system icons
- you may need to re-establish your Wi-Fi connection
- you will need to redo Windows updates subsequent to the build you have used for the repair install
- Windows.old will be created
- system restore will be turned off- you should turn it on again and I recommend you manually schedule a daily restore point.
- you will need to redo any language downloads including the display language if you changed that)
- inactive title bar colouring (if used) will be reset to default
- if Qttabbar is installed, you need to re-enable it in explorer (Options, check Qttabbar)
This is one of the better features of Win10: as each major build comes out, that's your updated reference build, and as updates are mostly cumulative, there will be few to do.


Please consider using disk imaging regularly. It's a brilliant way to
- preserve your system (and your sanity)
- back up your data
- restore your system to a previously working state in a relatively short time

Recommended: Macrium Reflect (free/commercial) + boot disk/device + large enough external storage medium.