Email Sync Problems

How to Recover Missing Outlook Data After Microsoft 365 Disappears

Maira Mehtab Oct 12, 2026 870 views

Question details

User needs to recover missing Outlook emails, contacts, and calendar items after Microsoft 365 apps unexpectedly disappeared from a laptop and were subsequently reinstalled.

Product: Microsoft Outlook
Device & OS: not provided
Scenario: Reinstalling Microsoft 365 applications after they disappeared while the laptop was left in sleep mode overnight.
Observed behavior: The applications reinstalled successfully, but local IMAP Outlook data (contacts, calendars, older emails) did not return, and only recent messages are visible on the webmail server.

Before you start

Log in to your email provider's webmail interface via a browser to verify exactly which emails are safely stored on the server before modifying your local Outlook profile.

Solution 1Recommended

Locate and Mount Previous Outlook Data Files (.pst / .ost)

Because IMAP accounts often store contacts and calendars locally on the computer, reconnecting your previous Outlook data file can restore the missing items.

Reinstalling Microsoft 365 usually creates a new mail profile but does not delete old data files. Finding the orphaned data files is the key to recovering your local contacts and calendars.

Open File Explorer

Press the Windows key + E to open File Explorer on your laptop.

Navigate to the Outlook data folder

Navigate to C:\Users\[YourUsername]\Documents\Outlook Files or C:\Users\[YourUsername]\AppData\Local\Microsoft\Outlook.

Locate old data files

Look for .pst or .ost files that have a modification date from before the Microsoft 365 applications disappeared.

Open the data file in Outlook

Open Outlook, click on File > Open & Export > Open Outlook Data File.

Access missing items

Select the old .pst file and click OK. It will appear in your left navigation pane, allowing you to drag and drop your missing contacts and emails back to your active IMAP account.

Locate and Mount Previous Outlook Data Files (.pst / .ost)

Hidden AppData Folder: If you cannot see the AppData folder, you may need to click on the 'View' tab in File Explorer and check the box for 'Hidden items'.

Solution 2

Force Sync Subscribed IMAP Folders

If older emails are visible on your provider's webmail but not in the newly installed Outlook, your IMAP folder subscriptions may need a forced refresh.

Free Microsoft Office alternative

Try WPS Office for a Stable, Lightweight Alternative

If you are experiencing unexpected application disappearances or stability issues with Microsoft 365, consider switching to WPS Office. It provides a robust, lightweight suite for documents, spreadsheets, and presentations without the heavy resource usage.

1. Download the installer: Visit the official WPS website and click 'Download WPS Office Free'.
2. Install the suite: Run the lightweight installation wizard, which completes quickly.
3. Open your files: Launch WPS Office and immediately open your existing Microsoft Office files without losing any formatting.

Highly compatible with Microsoft Office formats (.docx, .xlsx, .pptx).Lightweight design that runs stably on older or sleeping laptops.Familiar user interface requiring no steep learning curve.Free to use with built-in PDF editing capabilities.

microsoft office alternative - wps office

Frequently Asked Questions

Why did my IMAP contacts and calendars disappear after reinstalling Outlook?

IMAP protocols are strictly designed to sync emails with the server. Contacts, calendars, and tasks are usually stored in a local Outlook Data File labeled '(This computer only)'. When Outlook is reinstalled or the profile resets, it creates a blank local file, making the old data seem like it disappeared.

Does reinstalling Microsoft 365 automatically delete my Outlook data?

No. Uninstalling or reinstalling Microsoft 365 applications does not delete your Outlook Data Files (.pst or .ost). The files remain on your hard drive, but the newly installed Outlook may not link to them automatically.

Can my email provider restore my missing Outlook data?

If you are using an IMAP account, your email provider can only restore data that is saved on their servers, which you can verify by checking your webmail. They cannot recover contacts, calendars, or offline emails that were only stored locally on your laptop.

How can I back up IMAP contacts to prevent future data loss?

To protect IMAP local data, regularly export your contacts and calendars to a backup .pst file. You can do this by going to File > Open & Export > Import/Export, selecting 'Export to a file', choosing 'Outlook Data File (.pst)', and selecting your Contacts or Calendar folder.

Outlook & Email Problems