Suddenly having issues copying lots of cells from a filtered sheet

Hi,
I have an Excel 2007 file. It has a sheet with about 110,000 rows. I filter by one column and this reduces the view to 8777 rows. I then select all the visible rows in one column, copy them and paste them into a text document.
I did this a month ago without any error messages and I just checked all expected rows are in my text document. However, today I used exactly the same Excel file, same worksheet, same filter and selected the same rows to copy, but this time I got a message like this:
"Microsoft Office Excel cannot create or use the data range reference because it is too complex."
I did a little digging with Google and find that there is a limit on the number of non-contiguous rows you can select. It is 8192. Fair enough. However, I am perplexed as to how I successfully managed to do this a month ago on the same data without getting any messages. I know I did it in one operation (rather than, say, copy/pasting the first 5000 and then the other rows). Any ideas what could have changed? It is driving me nuts.

Thanks,

Adrian

Sorry I just realised that actually the file contents have changed between a month ago and today. My row count was 8150 and now it is 8777. Not too sure where the other rows have come from but this is clearly user error