Big Sur 11.6.6- Can not longer open email attachments.

Hello MSQ79,

Thanks for posting in Apple Support Communities. We recommend testing the issue in safe mode. Starting in safe mode allows your Mac to run certain checks, remove caches, and prevent login items from automatically launching. This can isolate possible third party issues. Use the steps and information in the following resource for assistance with safe mode: How to use safe mode on your Mac - Apple Support

Let us know the results. Be sure to include specific error messages and any other troubleshooting steps that you may have tried.

Have a great day!

There are numerous threads on this issue; you'll see there is no "fix"; just a couple laborious steps to very partially rectify on an attachment-by-attachment basis.

Please read them and you'll see.

Here's the "best" but it is no "fix" for sure -- https://support.microsoft.com/en-us/topic/ec9b3364-8acf-4f5a-9dc7-987fda68e2ec

Safe mode did me no good.

The best thing you can do is join the chorus and file a bug report with Apple.

This is squarely an 11.6.6 issue and since Big Sur is one OS behind, it's likely going to take noise from everyone for Apple to do a fix.

Sorry, I do not solution but am having the same issue! There are even calendar invites that cannot add to my calendar.

I am having the same problem. Every attachment requires me to open finder and then open the attachment. It's so confusing. APPLE please fix this bug. It's making my email impossible to use.