Whenever I edit a particular file, a BOM (hex sequence EF BB BF) appears at the start of the first line. This is invisible and ignored by PL/SQL Developer, but it breaks the script in SQL*Plus which we use for automated deployment. I have to remove it using a separate text editor prior to checkin.

It turns out that the file contains some multibyte characters in a comment (they appear to be MS Word smartquotes). Removing these stops the BOM appearing.

Are there any settings I am missing to control this behaviour? Unchecking "Unicode enabled" in Preferences > Options had no effect.

PL/SQL Developer version 11.0.2.1766

You can go to Tools > Preferences > File / Format and disable the "Save with BOM" option.

Normally the BOM is added to a source file if it contains characters that are not covered by the Windows system character set and therefore require Unicode encoding.

Great, thanks.