Dimitri Iliuk

Anita Fritz

7 simple steps to improve Outlook Shared Mailbox performance

Outlook Shared Mailboxes are a very popular approach for organisational email requirements due to their simple creation process. However, after a few years, the general feedback is that their performance slows with mailbox storage growth.

This blog explores seven simple steps to improve Outlook performance and how to cope with more extensive email storage requirements concerning Shared Mailboxes.

Starting with performance basics, we suggest reviewing the following:

1. Unlock your memory

Upgrade Outlook to the 64-bit version to ensure that it doesn’t suffer from memory limitations. If unsure of what version you are running, you can easily check from the File > Office Account > About Outlook menu option.

2. Check your add-ins

We have sighted environments in some cases with more than 25 Outlook add-ins, and often many are no longer required. Each Outlook add-in needs to be loaded on start-up and has the potential to slow things down and affect performance during usage.

3. Clean up and compact

Outlook performs best with a smaller and compacted mailbox store. The Clean Up Folder button is a great tool to remove redundant messages from every conversation in a folder for a quick tidy-up. If you still have old PST files attached to your Outlook, you should consider detaching them, as they may also contribute to poor performance.

4. Connectivity and hardware

Running Speedtest to compare results for wired and wireless connections is sometimes helpful. If there is a significant variance, then you should reassess your connection. If using old hardware, consider an upgrade, especially if it won’t run the latest version of Windows. The source mailbox location could also be impacted – if you are using Exchange Online, it’s not unusual to have your mailbox situated on the other side of the globe.

Moving onto Shared Mailbox considerations below:

5. Shared folder download

By default Shared Mailboxes will be downloaded to your workstation. Consider toggling the setting to determine what’s optimal for you. This setting can be found in the Control Panel > Outlook > Data Files > Cached tab.

6. Limits and boundaries

Without a license, the limit of an Outlook mailbox is 50 GB. Even with a license, it’s restricted to 100 GB. If the mailbox grows rapidly or is expected to be larger, an alternative solution such as archiving or SharePoint may be preferable.

7. Search and rediscovery

Once emails are stored in a Shared Mailbox, one of the key tasks is retrieving them. If emails are not easily found, then you should check that Windows indexing is running on a regular basis. It would be best if you also considered creating a folder structure to assist with finding items faster.

Should you continue to experience performance issues, storage limitations and poor search results with your Shared Outlook Mailboxes, then it’s worth exploring other more efficient options.


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