Just adding a comment to the topic. I was working with a large txt with approximately 700,000 rows and 13 columns. The file size was 136Mb. My version of mathcad is 15 (M045). The READPRN function did not report an error, but the function was only able to read approximately 600,000 rows. I removed 8 columns. The file was 53 Mb. With this size, the READPRN function could read all the rows. So, I think this limitation is not the absolute number 2,000,000 rows, but it is related to the amount of data in the file, maybe the file size. Just my humble opinion, based on that experience.