Excel 2007 - compatibilty check

[itsme]

I am using Excel 2007 at work where the default format for saving is 97-2003 (we're blocked from using .xlsx format) which is fairly sensible.  However when saving Excel does a compatibility check and warns if features may have to be auto adjusted.  I use one document where such a warning is given (relating to cell formatting).
You might assume that when reloading the document and then re-saving without changing anything you would not see the warning as incompatible features had been removed/adjusted on the last save.  But no, the same warning is given every time.  I suspect it is because of coloured cells although the colouring is solid and not using a pattern (the way patterns are generated has changed (I believe)).  Has anybody seen a solution to resolve this feature?

[Mike J]

Does everyone where you work use Excel 2007?  If so the compatibility check isn't needed.

Although, I've used excel 2007 and we had the default set to 97-2003 at work, and I never noticed any loss of features in any files - we are now set to Microsoft Excel Worksheet, as everyone has excel 2007 now.

What is a .xlsx format file?

[gonzo]

Excel pre 2007 was limited to 255 columns and about 50,000 rows. Excel 2007 has increased this number many times. Any data in the new fields won't be openable in the new format.

[bobajobrob]

What is a .xlsx format file?

Office 2007 format, it's a zip file containing a bunch of xml and other files.

[itsme]

Thanks for peoples thoughts on the issue.
It seems to be a revised colour code allocation that causes the problem, I think Microsoft is trying to unify things across the Office packages.  When I save an Excel sheet in a previous version, Excel (after warning about compatibility) converts the colours to 97-2003 format.  When the sheet is re-loaded it converts the colours back to 2007 format.