Outlook contacts missing after upgrading to Click-to-run versions of Office 365

Question

Outlook contacts missing after upgrading to Click-to-run versions of Office 365

Alan Shultz 20

Following a prompt from MS to update my Office 365 apps from "Microsoft Store" versions to "Click to run" versions, my entire Outlook Contacts have disappeared. Had three different categories -all gone. I have older backups to restore from, but would prefer to find the current file. Any direction?

VIZ 0 Reputation points

2025-08-29T00:02:53.31+00:00

I had the same thing happen to me. After updating Office 365 apps to "Click-to-Run" versions, all of my local Outlook contacts and calendar have disappeared.

Where was Outlook storing the records for my contacts and calendar before the update happened? Why did the update wipe out files locally stored on and used from my computer?

How can I recover the calendar and contacts from before the update?

Any help?

Thanks,

VIZ
Hornblower409-4652 1,460 Reputation points

2025-08-29T03:55:48.45+00:00

What happened? See my "Accepted Answer" below.

Can I restore? I have not seen any answers to that question.

Accepted answer

3 additional answers

Your answer

VIZ 0 Reputation points

2025-08-29T00:02:53.31+00:00

I had the same thing happen to me. After updating Office 365 apps to "Click-to-Run" versions, all of my local Outlook contacts and calendar have disappeared.

Where was Outlook storing the records for my contacts and calendar before the update happened? Why did the update wipe out files locally stored on and used from my computer?

How can I recover the calendar and contacts from before the update?

Any help?

Thanks,

VIZ
Hornblower409-4652 1,460 Reputation points

2025-08-29T03:55:48.45+00:00

What happened? See my "Accepted Answer" below.

Can I restore? I have not seen any answers to that question.

Answer 1

Hornblower409-4652 1,460

Old post (2020) but is probably still relevant.

https://www.slipstick.com/outlook/outlook-store-app/

installing Click-to-run version will delete all settings, Outlook profiles - basically everything stored in the registry and AppData\Local and AppData\Roaming paths. If you use an IMAP account with 'This Computer only" folders, you need to export the contents of those folders before you switch to Click-to-run

If you use an IMAP account and have entries in Calendar, Contacts, or Tasks folders labeled 'This computer only', export the contents to a pst or csv file before uninstalling [Store App] version of Office. Your profile will be deleted. You may also want to copy signatures to the "normal" default location.

Alan Shultz 20 Reputation points

2025-07-22T19:48:27.69+00:00

I'm guessing that this is what has happened - installing the "Click to Run" version wiped out my data & profile. I would have hoped that MS would have warned us, as this looks to be a know behavior, but in the spirit of continued enshittifacation, here we are.Thanks for pointing that out.

Next question - I have other Windows machines that I am away from and have not powered up since this change. If I made sure they were not connected to the web when opening Outlook, would I be able to recover a local copy of the data?
Hornblower409-4652 1,460 Reputation points

2025-07-22T22:09:35.8933333+00:00

>> If I made sure they were not connected to the web when opening Outlook

I would think so.

But before you start Outlook, use Mail from the Control Panel -
https://support.microsoft.com/en-us/office/change-or-update-email-account-settings-in-outlook-for-windows-560a9065-3c3a-4ec5-a24f-cdb9a8d622a2

[Show Profiles]
{For each Profile}
....[Properties]
....[Data Files]
....{For each PST file}
.... ....[Open File location]
.... ....Make a copy of the PST file to a safe place
....{Next PST}
{Next Profile}

If you can't do an export from Outlook once it starts (before the update), you can import from the saved PSTs once the update is finished.
https://support.microsoft.com/en-us/office/import-email-contacts-and-calendar-from-an-outlook-pst-file-431a8e9a-f99f-4d5f-ae48-ded54b3440ac#picktab=classic_outlook

Answer 2

IGYQ 5,650 Independent Advisor

Hi,

You can check your control panel first if your old Outlook profile is still there. Go to Control Panel → Mail/ Microsoft Outlook → Show Profiles. If you see your old profile, try to switch to that profile. Then open outlook and see if the correct one loads.

Alan Shultz 20 Reputation points

2025-07-19T21:42:30.8733333+00:00

Sorry- Don't see a "Control Panel." I'm on Microsoft 365 Ver. 2506, Build 18925.20158 Click to Run.

Tried to find other Profiles, had to restart to see profiles, saw only one "Outlook Profile," same thing - no contacts.

Also- all Calendar entries are gone missing,
Stefan Blom 310.3K Reputation points MVP Volunteer Moderator

2025-07-19T21:50:38.9+00:00

Alan,

Control Panel is from older versions of Windows, but it is still there in Windows 10 and 11 as well. You can start it by searching for Control Panel via the Windows Start menu. In Control Panel, you may have to change the view to small icons after which you should find the Mail (Microsoft Outlook) applet.
Alan Shultz 20 Reputation points

2025-07-19T22:24:44.4233333+00:00

Found it- thanks. Only one "Profile," still loads w/ blank Contacts and Calendar info.

Thanks though.
Alan Shultz 20 Reputation points

2025-07-19T22:48:09.28+00:00

And if it's helpful- I'm on "Outlook Classic" as I believe the old Outlook is called. I understand that "New Outlook" stores everything in the cloud. Could that be part of the problem?
Alan Shultz 20 Reputation points

2025-07-22T19:57:31.1966667+00:00

Only one profile listed in Control Panel, and it's the empty one. Thanks though.

Answer 3

Hornblower409-4652 1,460

If I understand correctly, it looks like you stored your Contacts and Calendar in a local PST file when you were using the Store Outlook. But when you updated to the Click-to-Run Outlook, it did not include this PST in the new Profile it created for you. So, the current problem is finding the old PST file.

PSTs are usually stored in :

C:\Users\YourUsername\Documents

or

%LOCALAPPDATA%\Microsoft\Outlook

Do you see any PSTs in these locations? If not, try a Windows Explorer search with "*.pst" in the search bar.

Once you find the PST(s) you then "Open" them in Outlook. This adds them to your Outlook Folder pane so you can see the subfolders inside the PST.
https://support.microsoft.com/en-us/office/open-and-close-outlook-data-files-pst-381b776d-7511-45a0-953a-0935c79d24f2#id0ebbf=classic_outlook

Alan Shultz 20 Reputation points

2025-07-20T21:02:31.9+00:00

Ok - I think we're getting closer; there is no .pst file in the \Users\Username\Documents folder, BUT there is an .ost file in LocalAppData\Microsoft\Outlook. BUT- Outlook won't open it - tells me the file needs to be only a .pst.

So- what now? I thought the .ost and .pst files did the same thing?

Also- the LOCALAPPDATA folder contains a folder for "Oulook Roaming" or similar. Are these links to cloud versions, perhaps?

And thank you for the assistance.
Alan Shultz 20 Reputation points

2025-07-20T21:14:00.8766667+00:00

And- my account is an IMAP account on Microsoft 365, so should use an".ost" file, correct? I can see a file but can't directly open it, and still have none of my contacts.
Hornblower409-4652 1,460 Reputation points

2025-07-21T01:38:07.6066667+00:00

1 >> an .ost file in LocalAppData\Microsoft\Outlook.

Check the Created date and size.
And from Outlook do: File -> Account Settings -> Account Settings | Data Files |

My guess would be that this is the new OST created for the new Click-To-Run profile and shows in | Data Files | as the Default.

2 >> Windows Explorer search with ".pst" in the search bar.*

Did this find anything?

3 >> I have older backup

In what form? A PST file? An Export?

Answer 4

IGYQ 5,650 Independent Advisor

On your Outlook Classic, try to open the PST file or OST file. Go to File - Open & Export - Import/Export. Enter the location of the PST or OST file.

Alan Shultz 20 Reputation points

2025-07-20T22:02:54.0066667+00:00

Tried that - Outlook will not open the .ost file - get a message of "The file you chose is not an Outlook Data File. You must select a new file of this type."

Thanks though.
Alan Shultz 20 Reputation points

2025-07-22T19:58:57.28+00:00

There is one .ost file in the path, Outlook will not open it.

Thanks though.

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Outlook contacts missing after upgrading to Click-to-run versions of Office 365

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