Solved New Outlook would not launch

win11freak · Dec 6, 2025

Today, when I attempted to launch the New Outlook nothing happened.

So I did a search and I deleted the OLK folder from the %Appdata% directory and that fixed the issue.

Has anyone ever faced this issue?

There were no error messages just the New Outlook didn't open at all.

It was working fine ever since I installed it but today had this issue.

secondsight · Dec 6, 2025

win11freak said:
Today, when I attempted to launch the New Outlook nothing happened.

So I did a search and I deleted the OLK folder from the %Appdata% directory and that fixed the issue.

Has anyone ever faced this issue?

There were no error messages just the New Outlook didn't open at all.

It was working fine ever since I installed it but today had this issue.

Yes me. I've had a hell of a time trying to solve this today. I think it has to do with the recent Preview release combined with the recent update to Outlook for Windows. Anyway....you are a star. This worked for me. Thanks.

I should point out that this folder is in C:\Users\<your_profile>\AppData\Local\Microsoft

I renamed mine Olk_tmp just in case and Outlook for Windows could then open. It also made a new Olk folder.

Had to setup the email accounts again but that is a minor thing.

Hornblower409 · Dec 6, 2025

If you find that just deleting the OLK folder doesn't fix it next time, there is:

The Nuclear Option. Completely reset your New Outlook for Windows profile. This will take you back to square one. You will have to add back all of your accounts and redo all your settings.

Exit the App. (Make sure it's not hiding in your Taskbar)

Uninstall it using the normal Windows Uninstall. Settings -> Apps ...

Open a Windows Explorer to %LocalAppData%\Microsoft. Find and delete the "Olk" folder (or rename to "Olk_OLD"). Find and delete the "OneAuth" folder (or rename to "OneAuth_OLD")

Install a fresh copy of New Outlook for Windows from the Microsoft Store. Outlook for Windows - Free download and install on Windows | Microsoft Store

Run it and add back your email accounts and redo all of your settings.

Drifter506 · Dec 6, 2025

@win11freak ....You sir, are a God!!!! I have been posting on the MS support page and multiple people having same issue. Naturally, MS moderators are useless. I reposted your solution there and gave you credit. May Santa give you a new super PC in your stocking!

Drifter506 · Dec 7, 2025

My Outlook file was in the C:\Users\(username)\AppData\Local\Packages\Microsoft.OutlookForWindows_8wekyb3d8bbwe

garioch7 · Dec 7, 2025

@win11freak ,

Thank you for sharing your solution. It worked for me. My Outlook for Windows has been non-responsive for a couple of days (no preview update installed). I used Revo Uninstaller Pro yesterday to uninstall it, rebooted, and reinstalled Outlook for Windows, but no joy. A Google search did not reveal the cause, so I just left it, hoping it would start working again just as abruptly as it quit working.

Your solution will help many. I salute you for sharing it.

Have a great day. You made mine.

Regards,
Phil

Tec Spot · Dec 7, 2025

Worked for me.....

I renamed all three folders
C:\Users\TecSpot\AppData\Local\Microsoft\Olk-old
C:\Users\TecSpot\AppData\Local\Microsoft\OneAuth-old
C:\Users\TecSpot\AppData\Local\Microsoft\Outlook-old

I Clicked the shortcut on my taskbar for outloook, and it set up everything automatically!
It Recreated all three folders automatically aswell!
THANKS for the advice and solution!!
def a bug in the win 11 25h2 and Preview release combined with the recent update to Outlook for Windows.

LisaB2025 · Dec 7, 2025

My Outlook suddenly reverted to the old version yesterday. Thank you very much for the solution. I had been working on it for a couple of days. I will add that at first I could not find the App\Data folder, which was also very frustrating. I finally found this:
"The AppData folder is hidden by default. To view it: In File Explorer, click on the "View" tab. Check the box for "Hidden items."
Once I did this, I could follow your excellent instructions above and got my New Outlook back. Again, thanks.

EB2XR6 · Dec 12, 2025

I was finding the Outlook for Windows App very slow after the recent update.
I renamed all three folders as per the post by Tec Spot:
C:\Users\Myusername\AppData\Local\Microsoft\Olk-old
C:\Users\Myusername\\AppData\Local\Microsoft\OneAuth-old
C:\Users\Myusername\\AppData\Local\Microsoft\Outlook-old
Uninstalled the Outlook App, re booted and reinstalled the App from the Microsoft Store.
It recreated the OLK and OneAuth but not the Outlook folder.
I think the Outlook folder maybe part of the Microsoft 365 Install? I have not Outlook that is part of Microsoft 365 since a fresh install a few weeks ago.

Setup the email accounts rebooted, Opened Outlook for Windows and it was still slow.
So I decided to try something else and went Nuclear.
I uninstalled the Outlook for Windows, deleted the 3 folders above, then I did Window Key R and deleted the temp files in %Temp% and Temp.
I also deleted all the Prefetch files.

Rebooted a fresh install from the Microsoft Store, set up the email accounts and the Outlook App is nice and responsive.

Solved New Outlook would not launch

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@win11freak ....You sir, are a God!!!! I have been posting on the MS support page and multiple people having same issue. Naturally, MS moderators are useless. I reposted your solution there and gave you credit. May Santa give you a new super PC in your stocking!