I think with the later versions of Excel the workbook limit is based on memory not a specific number here are Microsofts spec's.
Ah yes, I see. "Limited by available memory". Thanks for that, I'll bookmark that link.
So I guess the followup questions then become fairly obvious
- What version of Excel?
- How much memory is available?
- Why would someone have 2500 worksheets in a workbook? Wow!