Excel 2007 corrupting shared formulae in worksheet
 

I am using excel 2007. Seemingly at random, my users get the following error
when they try and open one of their saved sheets.

"Excel found unreadable content in <<filename. Do you want to recover the
contents of this workbook? etc.

When I click yes, I get a message with a list of "Removed Records: Shared
formula".

When I open up the underlying XML and compare the sheet before and after the
repair was done, I see that the corruption is to do with the way that the
shared formuale have been stored. An example of one of the repairs:


<c r="Q42" t="str"
<f t="shared" si="9"/
<vTotal potential catchment</v
</c

becomes

<c r="Q42" t="s"
<v1245</v
</c



I'm guessing that this is something to do with the fact that cell Q42 refers
to a shared formula which doesn't exist, but this is after the corruption has
taken place. This corruption seems to take place at random, even when the
user has not made any changes to that particular sheet.

Obviously, the thing that I'm most interested in is what is causing the
corruption in the first place.

Any help greatly appreciated.