Hi baron1180,
Does this problem occur to all types of attachments?
What's the version of your Outlook?
Please try to clear the Outlook Secure Temp folder and check if it can resolve the issue. For detailed instructions, you may refer to the article below:
https://www.howto-outlook.com/faq/securetemp.htm
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
Best regards,
Yuki Sun
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