One of our clients has several Microsoft Access databases which we developed, and when I need to work on them, we email the files back and forth. Recently, his email program has started renaming the attached files!! For some reason, it comes through named as database.zlh instead of database.mdb. So I did a little digging and it looks like some program along the way is doing that for protection, to prevent viruses, trojans and such. Here’s an article which details the different extensions given to files when they’re being automatically renamed. I’m still not sure which program is doing this, but it’s good to know why it’s happening and to be assured that the contents are not being changed, just the name. The solution is to give the file the proper extension when saving the attachment.