stop user from overwriting a workbook

In addition to Make it read-only you could also make a backup copy with a different name and have them work with the copy. Say "workbook 2 bkup" also have them try using a separate "Export/Save" folder to save and export files to, that doesn't have the original files in it.

That's a good idea in any case, but unrelated to enabling it to be overwritten.

but unrelated to enabling it to be overwritten

Note: Not the whole post.

It was related, the question was:

Is there any way to stop a user from accidentally saving an Excel workbook with the same name as my file and thereby overwriting my file?

Those are also legitimate ways to help prevent that from happening. You supplied making it read only. I offered my suggestions as a additional safety precaution.
But if the post is a violation of the forum rules, I apologize and the mod's can delete it.

No violation at all, you are welcome and invited to contribute in any thread. But please don't quote whole posts.