Missing lines in txt file when opened with Excel

[mirallye]

Hi,
I extracted data from an Oracle database that I could not save in Excel so I saved it as a txt file. Then I selected this file from the directory and right clicked to use Open with Excel feature. Strangely, the number of lines was not the same as if I first open Excel and select the file from the directory. More than 400 lines were missing with the Open with Excel method. I could replicate the pattern several times for different txt files. How could it be ?
Thanks

[pjwhitfield]

What is the format of the text file? is it comma separated etc? Also are you able to identify where in the file the missing records are? ie are they all at the start, end, middle or are they spread across the file?

[mirallye]

The file is a tab delimited and the missing lines are from different area of the file