READ COMPLETELY BEFORE JUMPING OFF THE PLANK:

See if this doesn't help - Open up 'My Computer' and then choose Tools |
Folder Options. Next select the [File Types] tab and scroll down the
alphabetical list until you see XML. You'll probably see something like
XLXML just ahead of it - and if that's there you'll see that it's probably
the expected file extension for XML files that are to be opened with Excel.

BTW: Before doing anything more, you can always perform these same
operations on one of the machines where it does work as expected and see what
that system's settings are for XML files.

Meanwhile the XML entry on the misbehaving machine probably shows something
like either IE 7 or XML Editor as the program to use to open .XML files with.
If that's the case, click the [Change] button and set things up the way they
are for the other, properly behaved systems, are set up with regards to
programs to use to open them.

BIG NOTE: Before you change anything, take copious notes regarding the
settings in place for handling XML files before changing any, just in case
this doesn't cure the problem and you want/need to go back to the way things
were.

"alex" wrote:

Hi,

I'm creating an XML Spreadsheet document and specifying <?mso-application
progid='Excel.Sheet'? processing instruction which tells Windows to open the
XML file in Excel.

That works on most of the client machines, howerver I have one PC where it's
opening it up in IE and seems to ignore the processing instruction.

Does anybody know how to troubleshoot this? I suspect it's somewhere in the
registry where this is set, but not sure what to search for.

The client machine is XP SP2, Excel 2003 version 11.8105.8107 SP2. When I
double click on a .xls the file opens in Excel correctly. But when I double
click on a .xml file (that has <?mso-application progid='Excel.Sheet'? in
it) it opens up in IE instead of Excel.

If this is not the correct forum please point me to more appropriate one.

Thanks,

Alex