Cached Exchange Mode in Outlook & How to Enable or Disable?

When the Exchange Server is connected to the Outlook, then it needs a special connection mode that will help it in managing the content in the mailbox and making the synchronization between the two applications.

There are two configuration scenarios in the Outlook while connecting to Exchange Server. First is the Cached Mode and the second one is Online Mode. The Online Mode works closely with Exchange Server and does not provide any offline copy of your mailbox. But the Cached Mode is quite beneficial for an active user.

In the Cached Mode, Outlook creates an Offline copy of your mailbox in an OST file and when the Outlook is not connected with Exchange, then you can continue to work on your mailbox and access your data through the OST file.

Cached Mode in Outlook

Microsoft rolled out the cached mode in Outlook in 2003 and since then it has proven itself a great feature for any user account whether individual or professional. Here are some key points that make the cached mode important in Outlook;

  1. Cached Mode recreates the OST file (offline copy of the mailbox) and saves it in the hard-drive folder.
  2. While Outlook works in the Cached Mode, then it looks in the offline OST file for all the information.
  3. In the cached mode, all the searches and reads are redirected to the OST file. Meanwhile, a separate process keeps looking for a connection with Exchange and sync the data.
  4. In the cached mode, Outlook copies the Global Address List to find the recipient of an offline mail.
  5. Users can search for emails in your inbox and write a reply even when they are offline.
  6. The user should enable the cached mode in different scenarios when there is an issue of better connectivity, latency, radio-based connectivity, and satellite connectivity.

How to check the Cached Mode is enabled?

You can easily identify the cached mode in the Outlook when you look at the bottom of the right-hand side. It will show ‘Connected to Microsoft Exchange’ which means that there is an active connection between Outlook and Exchange. You will also be able to find the data file of the OST file format in the App Data folder of Outlook.

Otherwise, if the Outlook shows the status as ‘Online with Microsoft Exchange’, then it means that you have an Online mode and there is no OST file in the App Data folder of Outlook.

How to enable the Cached Mode?

Although, the cached mode is enabled in the Exchange and Office 365 account. But, you can deliberately enable the cached mode by yourself.
Here is the simple procedure;

  1. Start Outlook, click File.
  2. Go to Account Settings >> Account Settings.
  3. Select the Account and click the Change button.
  4. Check the option ‘Use Cached Exchange Mode’ under the Offline Settings option.
    If you are an Office 365 user, then you will see a different option to check ‘Use Cached Exchange Mode to download email to an Outlook data file’ Check the option.
  5. Restart Outlook.

How to disable the Cached Mode?

If you want to disable Cached Exchange Mode, few steps are same as above, but clear the Use Cached Exchange Mode.
Here is the simple procedure;

  1. Start Outlook, click on File.
  2. Go to Account Settings.
  3. Select the Account and then click on the Change button.
  4. Check the option ‘Use Cached Exchange Mode’ under the Offline Settings option. Uncheck ‘Use Cached Exchange Mode’ to disable it.
  5. At last restart your Outlook.

If you are not finding the Cached mode option in your Outlook, then there can be multiple reasons behind it.

  1. There is not Exchange Account in your Outlook: The cached mode works only when your account belongs to Exchange and Office 365. If you are using an IMAP or POP account, then there will be no cached mode option.
  2. The Exchange Administrator has disabled the feature: Many times the Exchange Administrators disable such a feature to stop using the Outlook in the network downtime. You should contact your Exchange Administrator in such a scenario.
  3. Microsoft Terminal Service is present on the computer: There will be no Cached Mode in Outlook when Microsoft Terminal Service is installed on the computer.

After you have got all the basic information of the cached mode and its benefits to you, then you should make sure that the Cached mode is enabled in your account as it will accommodate all the information all the time. Because Exchange Server is a big application, so there are chances of latency in access to your data. Whenever there are increases latency, then the cached mode will help you in accessing the data without the interruption.

About Olaf Burch

Olaf works as a senior technology editor at Data Repair Tools. Fascinated by technology, he has more than 8 years of experience in the fields of data recovery, IoT, artificial intelligence and robotics. He enjoys the search and provision of DIY solutions to solve Windows technical problems. In spare time, he likes reading novels, and poetry. He also loves travel, rafting, trekking and so on.


  1. The cached exchange mode for Outlook is very beneficial for users who are facing connectivity problems or users, who work from different – different geographical location during the business tour. Its good Outlook feature for users like myself.

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