Have you ever had a stubborn file stuck in the trash which seems to defy all attempts at deletion? There are third-party apps you can use, such as
Super Empty Trash, which might do the trick. Or you could dive into Terminal and use the power of rm -rf to try to remove the file—of course, if you mess up doing that, you might remove everything on your hard drive. But say you’ve tried the other solutions, and yet you’re still stuck with the troublesome file. Here’s one more thing you can try.
Start by creating a new user in the Accounts System Preferences panel. It doesn’t really matter what name or access level you give the new account; it’s going to have a very short existence. Once the account is created, move the troublesome file from the trash into the /Users/Shared folder. Now (via Fast User Switching or a traditional logout/login), log in as the new user. Open the /Users/Shared folder, and move the troublesome file into the new user’s trash.
Now logout of the new account and log back into your main account. Return to the Accounts pane in System Preferences, select the account you just created, and click the minus sign (or just hit Delete). The system will put up a dialog box asking if you’re sure you want to do this, with three options: Cancel, OK, and Delete Immediately. Select Delete Immediately, and the troublesome file (along with the new user and the disk space they used) will disappear. (If you just press OK, the files from the deleted user will still reside on your drive.)
It may seem a bit time consuming to delete a file in this manner, but it’s very safe (much safer than the Unix solution), and will work on files that seem immune to all other solutions.