R: read.table and read.csv2 dropping/adding rows. No warnings

I have a datafile of 100,000 rows and 258 columns, delimited by semicolons. read.table(file, sep=";", fill=T, header=F) reads in 60,610 rows, and read.csv2(file, header=F) shows 100025 rows! col.names() us开发者_运维问答ing count.fields() makes no difference. The weirdest thing is that if I read the data into excel, save as csv, then use read.csv(), the import is spot on. But if I change the delimiter to "," in the original text file and try read.csv(), it again reads in only 60,610 rows. No warnings in any of the cases. What's going on?

If you look at the code for read.csv2 (just type read.csv and hit <enter> at your R commandline), you'll see it does nothing but call read.table with some default values. That should give you a hint on what is happening...