I reformatted my computer, updating from Windows 10 to 11, and reinstalled Outlook Classic. I botched the migration by failing to save the old settings such as individual profiles for the different Gmail addresses I filter into the Inbox, but I managed my way through that and it's pretty close to working how it was before the reformatting.



One thing that's significantly different is that for a certain few emails, it takes up to ten seconds to effectively open the email so I can process it, while Outlook freezes in the meantime. Once it completes the download of the message (I assume), Outlook then behaves as normal. This happens every time with one particular newsletter, and hardly ever with any other email.

I forwarded this email to my wife's Windows 11 machine with Outlook Classic, and her Outlook has the same delay opening it.

I did not have this problem with this newsletter on Windows 10.

I am wondering whether one difference is, when I loaded Microsoft 365 onto the machine pre-formatted with Windows 10, the suite included the full Outlook Classic. When I loaded the 365 suite onto the machine post-formatted with Windows 11, it was only the stripped-down skinny Outlook. I had to go to the MSFT store to find Classic to download. Is there some subtle difference between standalone classic and the Outlook previously included in the 365 suite that might be leading to this?

Otherwise, is there any setting change anyone can suggest that might address this weird and unusual delay?