Office 365 (Thunderbird) - Working Offline

Best Effort Support Only

This document contains instructions on using a non-Microsoft email client, such as Apple Mail or Thunderbird. Microsoft does not recommend these clients for use with Office 365, and there are often significant limitations in client functionality as a result.

Because of this, the DoIT Help Desk is only able to offer best effort support for these clients, and certain issues may require the use of a Microsoft client in order to be resolved. For more information on Office 365 client support, please see: Office 365 - Which clients/protocols will be supported?.

Offline access allows you to use Thunderbird on your laptop or desktop when you are not connected to the internet.

Note: If you tell Mozilla Thunderbird to make your IMAP account inbox available offline, all messages will automatically be downloaded to your computer and you can read them or write replies without being connected. Then whenever you are able to connect back up to the Internet, you can do a "send and receive".

How to work offline
  1. Open Thunderbird
  2. In the bottom left corner of the application window, you will see an icon of two computers

    two computer icon

  3. Click once on this icon
  4. A pop up box will ask if you would like to download messages for offline use

    download message window

  • Select Download Now if you would like access to your current messages
  • Select Later if you would like to write new emails and do not need access to your current messages
  • You are now working offline and no emails will send or be received
    • Tip If you prefer to either have your messages always downloaded or never downloaded you can check or uncheck the box on the pop up box

    How to return to working online from working offline
    1. Open Thunderbird
    2. In the bottom left corner of the application window, you will see an icon of two computers
    3. If this icon has a red X with the computers, you are currently working offline

      two computer icon

    4. To return to working online, click once on the icon with the computers and the red X
    5. You are now working online again and may send and receive emails


    Keywords:microsoft office365 o365 mozilla thunderbird work offline online   Doc ID:39652
    Owner:Help Desk KB Team .Group:DoIT Help Desk
    Created:2014-04-30 09:05 CDTUpdated:2020-08-13 18:22 CDT
    Sites:DoIT Help Desk, Office 365
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