And I don't want every attachment I've been sent by email to be deleted on the server side (not sure it would do that). But I'm a little worried that Outlook will just download them again. Is there an easy solution that I'm missing so I can keep using Outlook for Mac? I can access the attachments folder and I could delete the largest 100 attachments and I guess that would take a large bit out of this (but at 20MB an attachment, this would be 2gb, so I guess I'd have to do 1,000 attachment deletions, and then do this process every month or two). Note this file is just my work email and is about two years work emails, so it seems to be growing at about 5gb a month.

That is really the source of my local storage issues on my Mac (which only has 256gb of internal storage) as I've got cloud based storage solutions and external storage solutions for other things. I'm savvy enough to be able to find my Outlook folder on my Mac (yes it is hidden by default in the Finder) and can see the file sitting there holding about 115gb of data. You end up sifting through a lot of stuff outdated stuff. It is alway hard to Google stuff about Microsoft products for a Mac user because there is always a ton of stuff about older versions of these programs. I've googled this and seen articles confirming that the app is a 'locally cached email client'. It seems that Outlook for Mac downloads all emails and attachments locally.

Perhaps there is an Outlook pro and Mac user who can confirm something for me.

Outlook for mac for free