1: Install the latest updates
2: Make sure that Outlook is not in use by another process
If Outlook is in use by another process, this information is displayed in the status bar at the bottom of the screen. If you try to perform other actions while Outlook is in use, Outlook may not respond. Let the task in process finish its job before you try another action.
3: Check the problem which caused by external contents
- Prevent Outlook to download external contents. To do this, go to File>Options>Trust Center>Automatic Download, select the following two options:
- Don't download pictures or other content automatically in HTML e-mail option.
- Warn me before downloading content when editing, forwarding, or replying e-mail.
- Avoid sending such an email with external source.
4: Disable all add-in (Recommended)
- File > Options > Add-Ins.
- Select COM Add-ins, and then click Go.
- Clear all the check boxes in the list, and then click OK.
- Restart Outlook.
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