Over the past 3-6 months I have been having problems with attachments in Apple Mail always saying "Downloading". See attached screenshot. The files are not large by any means, but I have to force quit and relaunch Apple Mail multiple times to view them. Has anyone else experienced this problem? I did a clean install of macOS High Sierra 10.13.4, rebuilt my mailboxes, deleted my accounts and created new ones and it still says "Downloading" on every attachment in Apple Mail. This happens across multiple accounts and MacBook Pros.