Folders renamed then pop-up screen blocks Outlook

Question

Folders renamed then pop-up screen blocks Outlook

Paul Witcomb 0

On opening Outlook, the folders appear to be in a foreign language. After a few seconds, another screen appears rendering the application unusable (see attachment). None of the controls are then usable, apart from the close window button in the top right corner (X).

Thank you.

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3 answers

Your answer

Answer 1

Try the folder-name reset first, then reset the default folder language in Outlook on the web.

Exit Outlook.
Run these commands in order:
- Outlook.exe /resetfolders
- Outlook.exe /resetfoldernames
Sign in to Outlook on the web.
Go to Settings > View all Outlook settings > General > Language and time.
In Language, select the preferred language and enable Rename default folders so their names match the specified language.
Select the preferred date and time format, then select Save.
If the preferred language is already selected, switch to a different language, save, switch back to the preferred language, and save again.
Exit Outlook on the web, restart Outlook, and check whether the folder names return to the expected language.

If Outlook on the web shows an error such as Cannot localize the default folders, the mailbox already contains a folder with the same name as a default folder in that language. Rename the existing conflicting folder to a unique name, then repeat the Outlook on the web steps.

If administrator access is available, Set-MailboxRegionalConfiguration can also reset default folder names, but it requires admin permission.

References:

Answer 2

Francisco Montilla 31,820 Independent Advisor

Hello,

I cannot see the attachment you mentioned in your post. What exactly does the blocking pop-up say or look like?

Also it would help to know if you are using the Outlook desktop app on your computer or logging in through your web browser. Folders randomly changing to a foreign language along with a screen blocking the app usually points to an account that might have been compromised or a broken regional setting trying to force a sync.

Just hit me back with a description of what is on that screen so we can get to the bottom of this.

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Answer 3

Paul Witcomb 0

No, those commands would not run. Was advised that they were not recognised.

I opened Outlook today and found that I was just able to reset the language (from Vietnamese) after finding the correct section, i.e. Ngôn ngữ và thoi gian

Paul Witcomb 0 Reputation points

2026-11-04T21:07:26.0533333+00:00

I managed to fix it myself. When I opened Outlook today, I was not blocked by the pop-up screen that contained of Vietnamese text. When this was happening yesterday, I was reluctant to click either of the 2 buttons on the screen, as I had no idea what they would do. Anyway, as I said, I found the language setting section (by translating the options) and was able to get Outlook back to normal (English).
Francisco Montilla 31,820 Reputation points Independent Advisor

2026-11-05T15:10:31.7933333+00:00

Glad you got the language back on your own!

Just a heads up though, Outlook does not randomly switch to Vietnamese by itself. That is a classic sign that someone got into your account. Attackers often change the language so you cannot read the security alerts and set up forwarding rules to hide incoming emails.

I strongly recommend checking your inbox rules right away to make sure your emails are not being secretly forwarded or deleted. In Outlook, click the gear icon at the top right to open Settings, go to Mail, and then click Rules. If you see any rules you did not create, especially ones with weird names or single letters, delete them immediately.

After that, you should definitely change your Microsoft account password and check your recent sign-in activity just to be safe.
Paul Witcomb 0 Reputation points

2026-11-05T16:23:03.2366667+00:00

Thank you for replying; I do appreciate it. As in one of my previous replies, I found that the Vietnamese for 'Language and Time' is 'Ngôn ngữ và thoi gian'. I spent some time using Google translate until I got to this point, then gave it a try. To my relief, it worked!