How do I safely delete all emails on Entourage from my personal computer (but keep them on my network at work)?

I don’t use Entourage, and I obviously don’t know what your work-based email client is. So my advice isn’t specific, but general.

So, in general… I would think that if you open Entourage and simply delete the associations that it has with your work email server, then that former connection won’t be “alive” and able to do anything with mail that’s on the server at work. Next, you could find the file/s on your computer (most likely a large data file of some kind – if you know the extension that Entourage uses, then you could look it up that way) and simply delete these “local” files of your mail. Having the link broken between Entourage and your work client would ensure that the files won’t be rebuilt. – and won’t do anything with the remotely stored emails, either.

You could also check with your IT folks at work and find out from them the answer to, “If I accidentally delete all of the email in my server account tonight, will you be able to do a restore for me tomorrow?” Finding that they have nightly backups of the entire system – and can and will restore it to you if worse comes to worst – may give you the courage to take a more straightforward approach, and just hit the “delete” button with Entourage’s own settings in place to “not replicate to server – delete local replica only” (or whatever your command would be in Entourage).