Detected a problem launching new Outlook

Question

Detected a problem launching new Outlook

Regan Ramdath 0

I have a user who is running on the latest version of new Outlook for Windows when he recently started to get this error when opening new Outlook.

User's image

I have tried doing an online repair, a clean install and safe mode. All done with admin level privileges. I am able to open Outlook classic without issue and get the same error when trying to switch to the new version in app.

BryceSor 4,915 Reputation points Volunteer Moderator

2025-12-08T22:05:38.4233333+00:00

Hi Regan Ramdath,

Is this Outlook which is part of 365? and are you using Windows 11 and is that fully updated. Which version or build of Outlook are you using?
Regan Ramdath 0 Reputation points

2025-12-08T22:25:21.16+00:00

Yes this is part of 365. We are on Windows 11 with all current updates installed. Version 20251128003.09
BryceSor 4,915 Reputation points Volunteer Moderator

2025-12-09T05:37:33.7+00:00

Have you tried Jay option as this is a known fix for new Outlook not opening?
Regan Ramdath 0 Reputation points

2025-12-09T14:59:30.6766667+00:00

Not familiar with the Jay Option. Mind explaining it a bit?
Gabe Bratton 676 Reputation points Microsoft Employee Moderator

2025-12-09T16:42:08.6633333+00:00
The workaround is to go to this directory: %localappdata%\Microsoft\olk and then delete UserSettings.json. Here are the steps if you need more specifics:

Right click the Windows Start button and click Run

Paste this path in the Run box and click OK: %localappdata%\Microsoft\olk

Delete UserSettings.json

Start new Outlook and add your accounts back
Regan Ramdath 0 Reputation points

2025-12-09T18:20:25.0233333+00:00

Thanks Gabe, your solution worked!
Dustin 0 Reputation points

2025-12-10T13:39:10.9666667+00:00

I experienced this exact issue beginning this Monday (12/8) as well. I deleted the UserSettings.json file as instructed by Gabe and when I opened the new Outlook, it seemed like nothing happened, but after about 30 seconds the app loaded perfectly! Thank you!!!

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BryceSor 4,915 Reputation points Volunteer Moderator

2025-12-08T22:05:38.4233333+00:00

Hi Regan Ramdath,

Is this Outlook which is part of 365? and are you using Windows 11 and is that fully updated. Which version or build of Outlook are you using?
Regan Ramdath 0 Reputation points

2025-12-08T22:25:21.16+00:00

Yes this is part of 365. We are on Windows 11 with all current updates installed. Version 20251128003.09
BryceSor 4,915 Reputation points Volunteer Moderator

2025-12-09T05:37:33.7+00:00

Have you tried Jay option as this is a known fix for new Outlook not opening?
Regan Ramdath 0 Reputation points

2025-12-09T14:59:30.6766667+00:00

Not familiar with the Jay Option. Mind explaining it a bit?
Gabe Bratton 676 Reputation points Microsoft Employee Moderator

2025-12-09T16:42:08.6633333+00:00

The workaround is to go to this directory: %localappdata%\Microsoft\olk and then delete UserSettings.json. Here are the steps if you need more specifics:

Right click the Windows Start button and click Run

Paste this path in the Run box and click OK: %localappdata%\Microsoft\olk

Delete UserSettings.json

Start new Outlook and add your accounts back
Regan Ramdath 0 Reputation points

2025-12-09T18:20:25.0233333+00:00

Thanks Gabe, your solution worked!
Dustin 0 Reputation points

2025-12-10T13:39:10.9666667+00:00

I experienced this exact issue beginning this Monday (12/8) as well. I deleted the UserSettings.json file as instructed by Gabe and when I opened the new Outlook, it seemed like nothing happened, but after about 30 seconds the app loaded perfectly! Thank you!!!

Answer 1

Hi @Regan Ramdath,

Welcome to Microsoft Q&A forum.

Thank you for raising this to our attention and sharing steps have been taken.

If you have run online repair, a clean install and safe mode with administrator privilege, but the issue persists, you can safely delete the following folders from your system:

C:\Users(User Name)\AppData\Local\Microsoft\Olk
C:\Users(User Name)\AppData\Local\Microsoft\OneAuth

Steps to delete:

Close all Microsoft applications (Outlook, Teams, etc.).
Press Windows + R, type appdata, and press Enter.
Navigate to:
- Local > Microsoft > Olk
- Local > Microsoft > OneAuth

User's image

Select the folders and delete them.
Restart your computer.

Important:

Ensure Outlook and other Microsoft apps are closed before deleting.
These folders will be recreated automatically when you reopen the apps.

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.

Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to continuing the conversation.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

Regan Ramdath 0

The workaround is to go to this directory: %localappdata%\Microsoft\olk and then delete UserSettings.json. Here are the steps if you need more specifics:

Right click the Windows Start button and click Run
Paste this path in the Run box and click OK: %localappdata%\Microsoft\olk
Delete UserSettings.json
Start new Outlook and add your accounts back

Regan Ramdath 0 Reputation points

2025-12-09T18:20:02.7733333+00:00

This worked.

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Detected a problem launching new Outlook

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