Hi John,
Technically, Outlook won't rename your folders. It could be hard to find out who renamed the folder and why it was renamed, however, you may try to use the MFCMAPI tool to rename the folder to its original name. To do this, please follow:
1. Download MFCMAPI tool
here.
2. Double click on it to run, click Session > Logon and choose the profile you are using.
3. Double click on the default data file you are using for your account.
4. Expand Root - Mailbox (or Root Container)
5. Expand IPM_SUBTREE (or Top of Outlook Data Files)
6. Locate the folder you want to rename. Click on it twice so that you can edit the name. Change the name to what you want.
7. Close the window and return to the main MFCMAPI window. Exit MFCMAPI.
8. Open Outlook and whether the folder name was changed back successfully.
Hope this helps.
Regards,
Steve Fan
Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact
tnsf@microsoft.com.

Click
here to learn more. Visit the dedicated
forum to share, explore and talk to experts about Microsoft Teams.