Introduction

Changing to Cached Exchange Mode is recommended to improve Outlook’s performance and smooth end user computing experiences, and is recommended for all users, especially if Outlook is performing slowly, or if it hangs or freezes. This guide will explain:

1. Why CCCS-IT recommends enabling Cached Exchange Mode

2. How to enable Cached Exchange Mode

3. What differences you may expect when after enabling Cached Exchange Mode

Background (Why to Use Cached Exchange Mode)

In fall 2020, or thereabouts, CCCS-IT began receiving widespread reports of Outlook performing slowly, freezing, or hanging, sometimes repeatedly. While affected by these performance issues, Outlook would often consume massive system resources, such as processing power, memory, and network bandwidth, which would then cause other issues, including but not limited to:

• Calls and meetings being dropped

• Outlook, or other application crashes

• Slow or unstable Internet and/or VPN connections

• Computer, freezes, hangs, or outright crashes.

After investigating the problem and troubleshooting the mail servers extensively, the email administrators at CCCS-IT determined that Outlook’s Online Mode was the ultimate cause of the problem.

To remedy this issue with Outlook’s performance, our administrators recommend that all Outlook users change to using Outlook’s Cached Exchange Mode. Enabling Cached Exchange Mode typically results in an immediate improvement in Outlook’s performance, and often resolves seemingly unrelated computing issues.

How to Enable Cached Exchange Mode in Outlook

1. Open Outlook and click File to open the Account Information menu.
   
   

   Open

   

2. Click Account Settings, then click Account Settings… in the menu that drops down.
   
   

   Open

   

    

3. Select your email address, then click Change.
   
   

    

4. Under Offline Settings, check Use Cached Exchange Mode.

5. If the Mail to keep offline slider is not set to All, click and drag the slider to the rightmost position. This will ensure that Outlook makes all your mail items available, including your archived items.
   
   Please note: This setting will not change the mail retention policies, and you will still need to archive messages you wish to keep past 180 days. Messages in archive folders will also still be deleted according to the retention policies of their respective archive folders.

6. Click Next.
   
   

    

7. If prompted that you need to restart Outlook, click OK.

8. Click Finish

9. Close and restart Outlook.

When Outlook opens in Cached Exchange Mode for the first time, it will show all of your folders, but they will all be empty at first. This is normal and expected, Outlook will download all of your mail, which may take some time. For most users this will take about 15 minutes. If you have more than one thousand emails, it will likely take significantly longer to download all your mail items. However, Outlook will only need to do this once barring a major change, such as:

1. You get a new computer

2. Your computer suffers a catastrophic failure

3. Etc.

Enable Automatic Send/Receive for Cached Exchange Mode

1. Open Outlook and click File.
   
   

    

   1. Click Options.
      
      

   2. Click Advanced, then Send/Receive…
      
      

   3. Select the All Accounts group, then check Include this group in send/receive (F9) and Schedule Automatic send/receive every … minutes.

   4. Click Close.
      
      

      
      Note: If you change the send/receive frequency, it is recommended that you leave at least 10 minutes between every automatic send/receive for best performance.

   5. Click OK