Can I delete Mailbox Folder in Snow Leopard When I first got my Mac I used Mail for a little while, but now I always use Gmail in my browser directly.  My hard drive is nearly full and I've been using What size to try and work out where my space has gone and I found out that under Library &rarr; Mail there's a 50GB folder called IMAP (my email address).

I went into Mail and removed my email account and also deleted the local copy of my mailbox but after closing mail this file is still there.

Since I no longer use Mac Mail, can I delete it as it's taking up a lot of space, or will this cause other system issues?
Yes, it's fine to delete this folder — the only repercussions will be that you won't be able to access the emails in Mail.app until you reinstate the account.