Cannot Start Outlook in Offline Mode – Resolved

Outlook fails to start in offline mode, The problem could be the cached Exchange Mode settings or an unstable internet connection

Make sure Cached Exchange Mode is turned on and your internet is stable. You might also need to reset Work Offline mode or create a new Outlook profile.

When you switch Outlook to offline mode, you can only use it with limited internet to read and write emails, etc

OST files help users open and use Outlook without an internet connection. They store a copy of the information on the server on your local computer. This allows us to use Outlook without an Internet connection. Once the internet is restored, the OST file synchronizes with data on the server mailbox.

Error – ‘Cannot Start Outlook in Offline Mode’

Although Offline mode is useful, some users complain about issues when using it. This article focuses on ‘Outlook not starting when Offline’ and potential solutions. The error reads:

‘Cannot start Microsoft Outlook. Cannot open the Outlook window. The set of folders cannot be opened. The operation cannot be performed because the connection to the server is offline.

This error is commonly seen when you try to start Outlook without an internet connection. It is not seen when you already have Outlook open and switch to offline mode.

Solution 1: Uncheck Favorites in Mail Navigation to Open Outlook Offline

The folders in the favorites list (mainly IMAP folders) wait for a server connection. This creates problems when Outlook is ‘Offline’. To resolve this, turn ‘OFF’ Favorites on your Email navigation.

To do so, go to the ‘View’ menu and uncheck ‘Favorites’ in the folder pane. This helps resolve your issue in some cases.

Solution 2: Re-create the OST file to Start Outlook Offline

Sometimes, if your OST file is damaged, Outlook may have issues working in Offline mode. To resolve the Outlook error, you can delete the old .ost file and re-create the file. To delete the old .ost file, follow the steps below.

1. Close Outlook and open Run by pressing the Windows + R keys
2. Then type ‘%LOCALAPPDATA%\Microsoft\Outlook\’ and hit Enter
3. Select the ‘.ost’ file and hit Delete to delete the file

Once you have deleted the old.ost file, you can create a new OST file easily by following the steps below.

1. Go to the File menu and click on Info
2. Select Account Settings > Microsoft Exchange > Settings
3. Click on More Settings and choose Advanced Tab > Offline folder file settings
4. Choose a destination to save your OST file and choose Ok.
5. If you receive an error ‘.ost file couldn’t be found. Would you like to re-create it? Click ‘Yes’ and proceed.

This will create a new OST file. Now restart ‘Outlook’ and check if the issue is resolved.

However, if you do not want to go through the hassle of deleting your old .ost file and re-creating a new one, you can use OST to PST converter. This will help you repair the OST file and convert it to PST. After conversion, all Outlook items such as emails, contacts, calendars, etc. will be saved to the new PST file.

The software works with all versions of Outlook. It can repair corrupted .ost files with synchronization issues or due to hardware or software errors in only a few clicks.

Avoid corruption in .ost files

To prevent corruption in .ost files, always close Outlook properly. Avoid syncing files with the server during a slow internet connection. Ensure the .ost file stays within the size limit to prevent corruption or damage. If you’re facing issues with a large PST file, click to learn how to fix a PST file that is too large.

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About the Author: Tony Landry

Tony Landry is a Web Content Editor at Remo Software. He loves to write, edit, and manage content for users trying to troubleshoot and fix problems on Windows, Outlook, storage drives, and Cloud storage networks. With an aptitude that transcends writing, Tony is recognized as a Microsoft Outlook, Word, and PowerPoint expert. His comprehensive solutions…