Apparently an asleep-at-the-wheel engineer made a coding change that causes QuickBooks to open hundreds of your attachments (all of them?). And the change went untested as the rest of their team was also not paying attention.

Other posts here say that if you get all of the latest updates for QuickBooks that it seems fixes. You may want to restart the computer as well.

If that doesn't work, you can rename the attachments folder, though that will break access to all of the attachments. See:

https://quickbooks.intuit.com/learn-support/en-us/other-questions/rename-attach-folder-to-attach-old...