Problem uploading XLS

I had a file of 1593 records so I split it up into one file of 1450 and the rest on the other file. When I try to upload the file of 1450 it kept telling me it had to be less than 1500. I highlighted about 1,000 rows down and deleted (even though they were blank) and the upload worked. Now though in the import wizard it only goes over to column 13 when there are 15 columns. This hasn't happened on any other spreadsheet besides this one.