When I try to open certain Excel files, I get this message:

Unable to read file. [OK]
Unable to read file. [OK]

Errors were detected ... MS was able to open the file by making the
repairs below. Save the file to make the repairs permanent.

Damage to the file so extensive that repairs were not possible. Excel
attempted to recover your formulaes and values, but data may have been
lost or corrupted.

The resulting file is devoid of any formatting, and some formulaes are
gone. It's really no use since it takes so much time to reconstruct
these files. I've been saving 4 different versions of the files that
I work on, in case this happens. It never happens when I'm working on
the file. When I close the file and try to come back in, that's when
it happens.

When I go to MS Excel support, the answer suggests that the problem
occurs when using Excel 2000 and 2003 to make changes to the same
Excel file. I don't think that's the case. The macro setting is
medium and higher. I have not had any problems with viruses.

One thing I do notice, however, is that these are pretty extensive
Excel files. They have imported sheets from other Excel files. When
I open, I chooose no when Excel asks me to update the links. Could
this be a problem? Should I be breaking the links? But I've been
operating like this for almost 5 years now and have never had this
problem. What could be going on here?

Help!