Using Classic Outlook on Windows for personal email, calendar, and contact management
Dear Nanyan Chen
Thank you for posting in Microsoft Community, we are glad to assist you here.
Based on your description, we understand you would restore deleted meeting from Outlook, please follow below steps:
Step 1: Open the folder view in the Navigation Pane with pressing the Ctrl + 6 keys in a meantime.
Step 2: Open the Deleted Items folder, find out the deleted meeting or contact, and then drag it to the original Calendar/Contact folder.
If you have permanently deleted a meeting or contact in Microsoft Outlook, you won’t find out the deleted meeting or contact in the Deleted Items folder. Actually, you can still restore the permanently deleted meetings or contacts with the Recover Deleted Items feature.
Step 1: Shift to the Mail view, and then click the Recover Deleted Items button on the Folder tab.
Step 2: In the opening Recover Deleted Items dialog box, find out and select the meeting or contact you have permanently deleted, and then click the Recover Deleted Items button. See screen shot below.
Note: This method only works with Exchange accounts.
Hope this is helpful and thank you for your time,
Regards,
Microsoft Community