Binary File Replacement Warning
The above warning message is provided if replacement confirmations are enabled (Options-Replace) and if Search and Replace detects that a replacement is about to be made in a ‘binary’ file such as an .exe file, word processing document, spreadsheet, graphics image, etc.
See Word Document Notes for more information about replaces in proprietary format files such as .doc, .xls, .mdb, .pdf, and so on.
To disable this prompt, turn off replacement confirmations in Options-Replace.