FIX: Outlook Error 1025 “Invalid Mailbox Name” for Gmail on Mac

Error Code 1025 Invalid Mailbox Name error occurs on the Macs running Outlook usually when your e-mail configuration is incorrect or if the settings have been changed, such as when you re-configure your e-mail account. ie. when folder settings are changed on an IMAP Account.

One user reported that after changing the visibility of IMAP folders, they started receiving this error. The same settings worked on Apple Mail and other variations of Outlook and other e-mail clients. This issue was specifically triggered in Outlook 2011.

To resolve this issue, you will need to delete and re-add account as IMAP.

1. First, check if your account type is a POP or an IMAP. If it is POP, you will need to export or save the data because you will need to re-add your account as IMAP Account and delete the existing account. (Google It)
2. Next, Open your internet browser, navigate to www.gmail.com and log in with your account.
3. After logging in to your Gmail account, go to Settings. You will find this under the gear icon in the top right corner of the page.
4. Select the Forwarding and POP/IMAP” tab and modify the following commands.

Enable IMAP

Disable POP

4. Click the Save Changes
5. Next you will need to configure Gmail “Show in IMAP” settings in the account. This is done by selecting the “Labels” tab in Settings to select folders to sync to IMAP. Here, you choose what folders you need visible in Outlook; if you want all folders to show up then leave settings as is.
6. Once you have finished with this you can then re-add your Gmail account as IMAP.
7. Under the Tools drop down menu, select Accounts.
8. Click on the + to add an email account. Enter your Gmail email and password and press “Add Account”. When you see the green button, you know you are connected.
9. Click on the Advanced tab in the bottom right corner. And configure the folder settings as described in the following steps.
10. Under Folders Tab, choose Store junk messages in this folder: select “Junk E-mail”.
11. Under the Move deleted messages to this folder: select “Never”
12. Go to the Server Tab, and enter [gmail] as IMAP Root Folder.

After you have finished these steps, Close Outlook, restart your machine and open Outlook. All the messages from the server will be downloaded again, and the account should now work fine.