Display of Emails older than 12 months in folders

In classic Outlook for Windows, this behavior is controlled by the Cached Exchange Mode setting Mail to keep offline (also shown as Download email for the past in later versions). To display all emails (including those older than 12 months) in folders, increase this setting to All.

Follow these steps in classic Outlook:

1. Select File > Account Settings > Account Settings.
2. On the Email tab, select the Exchange or Microsoft 365 account, then select Change.
3. Under Offline Settings, move the Download email for the past: (or Mail to keep offline) slider all the way to the right to All.
4. Select Next, then Done.
5. Restart Outlook to allow it to download all mailbox items.

After this, Outlook will synchronize the entire mailbox instead of only the last 12 months, and older emails will appear in the folders once they finish downloading.

Note that this setting affects how much mail is cached locally in the Offline Outlook Data (.ost) file; items older than the configured period always remain on the server and become visible locally once the slider is increased and synchronization completes.

References:

• Work offline in Outlook
• Only a subset of your Exchange mailbox items are synchronized in Outlook

Hi @Julie Slavens, 

Good day. Hope you are doing well. 

I understand how disruptive this may have caused when only emails newer than 12 months are displaying. According your concern, this behavior is expected when Cached Exchange Mode is enabled. By default, Outlook is often configured to download and display only the most recent 12 months of emails to improve performance. Emails older than 12 months are not deleted; they are still safely stored on the mail server and simply not fully synchronized to the local Outlook client.  

To resolve the issue, please follow these steps:  

1. Adjust Cached Exchange Mode 

To reduce the effect of the Outlook offline data file (.ost), the default number of months that are configured for your profile varies by the size of your hard disk. To change the number of selected months of email to synchronize with your cached mode ".ost" file, please follow these steps: 

• In the Outlook desktop application, go to File > Account Settings > Account Settings. 

• Select your email account and click Change. 

• Under the Offline Settings section, look for a slider (often labeled "Mail to keep offline"). 
• If the slider is set to 6 month or 1 year, slide it all the way to the right to "All." 

• Click Next and then Finish. 
• You must restart Outlook for the change to take effect. It may take some time for the older emails to download. 

2. Clear Outlook cache  

• Close the Outlook app.  
• Press the Windows + R keys simultaneously to open the Run dialog box.  
• Type the following path into the Run box and press Enter:   %localappdata%\Microsoft\Outlook\RoamCache  

• Click anywhere within the folder, press Ctrl + A to select all files, and then press the Delete key to remove them. Alternatively, you can right-click the selection and choose the Delete option from the context menu.  

• Restart Outlook and try again.  

3. Check the Outlook Web App (OWA) 

• Log in to Outlook on the Web (your email through a web browser). 
• Use the search bar and look for the old emails. 

Once this change is applied, Outlook will begin synchronizing older emails. Depending on your mailbox size, this process may take some time to complete. 

Please note that if these settings is unavailable or cannot be changed, it may be controlled by your organization’s IT policies. In that case, your IT administrator would need to adjust it. 

I hope this information is helpful. Please follow the steps above and let me know if it works for you. If not, we can continue working together to resolve the issue.  

Thank you for your patience and understanding. If you have any questions or need additional assistance, please don’t hesitate to reach out so I can continue to support you. If you found the response useful, please consider marking it as accepted, as this may help other community members who are looking for similar guidance.  

I look forward to continuing the conversation.

If you have extra questions about this answer, please click "Comment". 

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