This is why I always write a BOM in CSV files (yes, even though it's UTF-8 and it shouldn't have a BOM). Excel will actually respect it. The bigger problem is

This is why I always write a BOM in CSV files (yes, even though it's UTF-8 and it shouldn't have a BOM). Excel will actually respect it. The bigger problem is when Excel tries to be helpful and reformats the data upon opening the file. I can't remember the intricacies, but it used to behave differently whether you opened it from a local path or directly from a browser. I seem to recall using an "incorrect" MIME type helped with that.