I wrote an excel macro and ran it. Everything worked right, but after I saved the file in an ".xlsx" format it won't re-open. It tries to open it for a while, but eventually says the file has been corrupted. I then tried to save the file in a macro-enabled format ".xlsm" and it did the same thing. I eventually saw the binary format ".xlsb" and saved it like that, and the file opened perfectly. Does anybody know why this is happening?