I changed a .txt file to be saved with a .xls extension. If I try
opening the file in Excel, I get an error saying "the file has a
different extension than specified by the file extension....verify if
the file is not corrupted...do you want to open file?" Then, if I
click "Yes", Excel will open the file in good format. It seems like
the problem is that the file is not recognized by Excel as a .xls, but
opens it without any errors. If I open the file and saveas a .xls,
then the next time it opens up fine.

Is there a way around this, or some setting that can be changed in
Excel that does not prompt this for ever file that I have? Thanks!