Sure. Basically, you create a text file somewhere the user won't easily find it that has some kind of a value in it to indicate this copy of the database is registered. I like to hide it in the C:\Windows\System32 folder, but of course that means you have to tell the user they need to run Access "As Administrator" or else you can't write to that file. But hey, that's the price of paying for the software. No Admin, no install. LOL. Then every time the database opens, you just read that file in and see if it's still there. You can even encrypt in the file an expiration date if you want them to pay for an annual license. I've got a whole seminar devoted to this topic.