Outlook 365 won't launch when internet is out

Copper Contributor

If my desktop Outlook 365 is already open, I can switch back and forth to work Offline via Send/Receive "Work Offline" switch in the ribbon.


But if internet is out before I launch Outlook, Outlook 365 won't launch even though I've got "Use Cached Exchange Mode to download Exchange email" checked and my Outlook Data File includes all my email. I get an error message that Outlook can't locate my Exchange account.


I've read that there's an outlook 365 "Prompt me at startup so I may choose to work offline or online check box," but I can't find it. 


Is there a different way?

2 Replies
best response confirmed by bgeller (Copper Contributor)

Hello @bgeller,

If you're experiencing difficulties launching Outlook 365 when the internet is unavailable, it's likely due to the cached Exchange mode not being enabled or configured properly. Here are a few steps you can take to resolve this issue:

  1. Verify Cached Exchange Mode settings:

    • Open Outlook and go to the File tab.
    • Select Account Settings and then click on Account Settings again.
    • In the Account Settings window, select your Exchange account and click on Change.
    • Ensure that the "Use Cached Exchange Mode" option is checked.



  2. Adjust Cached Exchange Mode slider:

    • While still in the Account Settings window, click on the "More Settings" button.
    • In the Advanced tab, locate the Cached Exchange Mode slider.
    • Move the slider towards the right to increase the amount of data that is cached.
    • Click OK to save the changes.


  3. Check Outlook profile configuration:

    • Open the Control Panel on your computer and search for "Mail" or "Mail (Microsoft Outlook)."
    • Open the Mail applet and click on the Show Profiles button.
    • Ensure that your profile is selected and click on Properties.
    • In the Mail Setup window, click on the Email Accounts button.
    • Verify that your Exchange account is listed and properly configured.
  4. Enable prompt for offline/online mode:

    • Although the "Prompt me at startup so I may choose to work offline or online" option is not available in Outlook 365, you can achieve a similar result.
    • Create a shortcut to Outlook on your desktop.
    • Right-click on the shortcut and select Properties.
    • In the Target field, add "/safe" (without quotes) at the end of the existing path.
    • Click OK to save the changes.
    • Whenever you want to launch Outlook and work offline, use this modified shortcut.

By following these steps, you should be able to launch Outlook 365 and work in cached mode, even when the internet connection is unavailable.

Kindest regards

Hello @LeonPavesic 


Your #4 step suggestion works. Thank you!

I confirmed your Steps #1 - 3 and they were already configured correctly. So, I needed the shortcut.

When I tested by disconnecting from internet before launching with your modified Outlook shortcut, a "Choose Profile" window opens even though there's no checkmark in the box for "Prompt for a profile to be used." Odd but no big deal.
Secondly, after successfully launching in Offline Mode using the shortcut, my Reading Pane is missing, despite the View/Reading Pane icon correctly displaying that the Reading Pane should be at the Bottom. Using the shortcut, Outlook launches without a Reading Pane whether online or offline.


However, launching from my Start menu, with internet, my Reading Pane is restored to Bottom.