Quick fix: Region setting resets after Windows updates because feature updates may re-detect the region from your Microsoft Account billing address or IP geolocation. Open Settings → Time & language → Language & region, set Country or region back manually. To make it persist, also update your Microsoft Account’s country at account.microsoft.com to match.

You set Region to United Kingdom (or Japan, or Brazil, or wherever). Reboot the PC. Region is back to United States. Or after a feature update, the same thing. The cause is Windows’s auto-detection during install or update overriding your manual choice. Several places need to agree for the setting to stick.

Symptom: Region setting in Windows reverts to United States after reboot or feature update.
Affects: Windows 11 (and Windows 10).
Fix time: ~10 minutes.

What causes this

The Region setting (Country or region) affects: which Microsoft Store apps you see, which Windows Update channel you’re on, date/time formats, currency display, and which version of Cortana/Edge default search you get. Windows reads region from: your Microsoft Account billing country, IP-based geolocation during install, OOBE setup choices, and explicit Settings overrides.

Feature updates occasionally re-evaluate region from MSA or IP and overwrite your manual setting. The fix is to make all sources agree on the same country.

Method 1: Set region in multiple locations

Make sure all settings align.

Open Settings → Time & language → Language & region.
Set Country or region to the desired country.
Set Regional format to match the country (e.g., English (United Kingdom) format for UK).
Update Microsoft Account billing country: open browser to account.microsoft.com/profile, sign in. Click Edit name and country/region. Change country to match. Save.
For Windows 11 Pro: open Group Policy Editor (gpedit.msc) → Computer Configuration → Administrative Templates → System → Locale Services → Restrict selection of Windows menus and dialogs language. Configure if you want to lock region.
Sign out and sign back in for all changes to apply.
Verify in Settings → Language & region: country and regional format both match.

When all sources agree, Windows doesn’t auto-revert.

Method 2: Persist region via registry

For when feature updates keep reverting despite MSA alignment.

Open Registry Editor (regedit).
Navigate to HKEY_CURRENT_USER\Control Panel\International.
Verify LocaleName matches your region (e.g., en-GB for UK, pt-BR for Brazilian Portuguese).
Verify Locale is the correct LCID (e.g., 0809 for English UK, 0416 for pt-BR).
Navigate to HKEY_CURRENT_USER\Control Panel\International\Geo. Verify Name matches the country code (e.g., GB for UK, BR for Brazil, JP for Japan).
For changes to apply system-wide (not just current user), also update HKEY_USERS\.DEFAULT\Control Panel\International.
To apply to new user accounts: Control Panel → Region → Administrative tab → Copy settings → tick “Welcome screen and system accounts” and “New user accounts”.
Reboot for changes to fully apply.

This locks region at the registry level, harder to be overridden during updates.

Method 3: Use PowerShell for scripted/repeated region setup

For multiple PCs or repeated post-update fix.

Open Terminal (Admin).
Set culture (regional format):
```
Set-Culture -CultureInfo "en-GB"
```
Replace en-GB with your target locale (pt-BR, es-MX, ja-JP, etc.).
Set home location:
```
Set-WinHomeLocation -GeoId 242
```
GeoId reference: 242 = UK, 32 = Brazil, 122 = Japan, 244 = United States. Look up at docs.microsoft.com/windows/win32/intl/table-of-geographical-locations.
Set system locale (affects display language):
```
Set-WinSystemLocale -SystemLocale "en-GB"
```
Requires reboot.

Set language list (affects keyboard and UI):

$LanguageList = New-WinUserLanguageList -Language "en-GB"
Set-WinUserLanguageList -LanguageList $LanguageList -Force

Save as a .ps1 script you can re-run after each feature update.
For corporate deployment: use Intune to deploy region settings via Configuration Profiles.

This is the right path for IT-managed PCs or for users who set up many devices.

How to verify the fix worked

Open Settings → Time & language → Language & region. Country shows the desired country. Regional format matches.
Open Microsoft Store. Items shown reflect your region (UK store shows GBP prices, etc.).
Verify date format in File Explorer: matches regional format (e.g., DD/MM/YYYY for UK).
After a feature update or reboot, settings should persist.

If none of these work

If region keeps reverting after feature updates despite registry and MSA alignment, two causes apply. Image-based deployment: PCs imaged from a master image with default US locale will re-baseline to US during feature updates unless the image is regenerated for the new region. Re-image with sysprep using your region’s settings. Group Policy enforcement: corporate-managed PCs may have Group Policy enforcing a specific region. Run gpresult /h C:\gpresult.html — look for Locale or International policies. Contact IT to change them. For Microsoft Store availability: if you live in country A but want B’s store offerings, set MSA country to B and Windows region to B. The Store uses MSA country for product availability, not just Windows region. For Cortana/Edge defaults: changing region doesn’t change which Bing market the search defaults to until you sign out and back in. Sign out, then sign in to refresh service tokens. For users in countries Microsoft hasn’t finished localizing (some African and South American countries): partial regional support means Region setting can’t fully match. Live with US-default for some Windows features.

Bottom line: Set Region in Settings + Regional format + MSA billing country + Windows region all to the same value. After alignment, Windows stops auto-reverting during updates.