How to improve sluggish Outlook

1. Clean Your Mailbox

• Delete Unwanted Items: Go through your emails and delete any messages or folders you no longer need.
• Empty the Deleted Items Folder: Make sure to empty this folder to free up space.

2. Compact the Data File

After cleaning up your mailbox, you can compact the data file:

• Open Outlook.
• Go to File: Click on the File tab in the top left corner.
• Access Account Settings:
  • Select Account Settings.
  • Click on Account Settings again from the dropdown.
• Select the Data File:
  • Navigate to the Data Files tab.
  • Choose the data file you want to compact.
• Compact the File:
  • Click on Settings.
  • In the Outlook Data File dialog, select Compact Now.
  • Click OK to confirm.

3. Update your Outlook

Windows (Outlook for Microsoft 365 / Office 2019/2021)

• Open any Office app (Outlook, Word, Excel).
• Click File > Account (or Account Office) on the left.
• Under Product Information look for Office Updates and click Update Options.
• Choose Update Now. Wait—updates download and install automatically.
• Restart Outlook if prompted.

Mac (Outlook for Microsoft 365 / Office 2019/2021)

• Open Outlook.
• From the top menu choose Help > Check for Updates.
• In Microsoft AutoUpdate, click Check for Updates.
• If updates are available, click Update (or Update All). Wait for installation and restart Outlook if asked.