Hi Emeli,
Thank you for reaching out. My name is Furkaan, a user just like you. I’d be happy to help you with your concerns. There are several reasons why you might not be able to delete a folder in Outlook. Here are two possibilities and how to fix them:
Built-in folders:
Certain folders in Outlook, such as the Inbox, Sent Items, and Trash, are critical to the program's operation and cannot be deleted. There is no delete option when right clicking on these folders.
Folder permissions:
If you created the folder, there may be a permissions issue preventing deletion. You can try to fix the following issues:
Webmail: Try signing in to your Outlook.com account using a web browser. Navigate to the folder you want to delete and see if the option is available. If this is the case, deleting it via webmail may solve the problem. Unsubscribe from Folder (For IMAP accounts): If you're using an IMAP account with Outlook, the folder might be subscribed to locally. Here's how to unsubscribe:
Right-click on your Inbox (of the account with the folder you want to delete). Select "IMAP Folders." Choose the "Subscribed" tab. Highlight the folder you want to delete and any subfolders. Click "Unsubscribe" and "OK." Try deleting the folder again. If none of these solutions work, it's best to contact Microsoft support for further assistance specific to your account.
If you have any additional questions or concerns, please don’t hesitate to reach out. Give back to the Community. Help the next person who has this issue by indicating if this reply solved your problem. Click Yes or No below. Best Regards, Furkaan