Restore Outlook calendar event

1. Check the Deleted Items folder (for Exchange accounts)
Switch to Calendar view on the left navigation bar in Outlook
Click on "Folders" > "Recovery of deleted items" in the top menu bar
Find the deleted calendar event in the pop-up window
Select the event that needs to be restored and click the "Restore" button
Note: This method is only available for Exchange accounts and is usually valid for 30 days after deletion
2. Using OST / PST backup document recovery
Perform "File" > "Open and Export" > "Import / Export" in Outlook
Select Import from another program or file
Browse and select the PST file previously backed up
Select "Include Subfolders" and complete the import
3. Recovery via Mail Piece Server (Exchange Administrator)
Administrator login to Exchange Management Center
Navigate to "Recipients" > "Email"
After selecting the user's mailbox, click on "..." > "Recovery of deleted items"
Set a time range and search for calendar events
Select the recovery target (original mailbox or new mailbox)
4. Using Windows Document Recovery Tool
Download official Microsoft Windows File Recovery tool
Run Command Prompt as Administrator
Execute the recovery command (example):
winfr C: D: /n *.pst
Import recovered PST file into Outlook
5. Check other calendar views
Possible scenarios:
Events may have been misclassified to other calendars
Filtering conditions may hide the event
Time zone setting change caused events to "disappear"