Using default data type sizes (field length) can lead to an “unexpected end of file” error message. This generally occurs with the money and datetime data types when only part of the field occurs in the data file (for example, a datetime value of mm/dd/yy with no time component) rather than an entire string, as expected by Microsoft® SQL Server™. When using the default size option, SQL Server expects to read 24 characters (the length of the datetime data type when stored in char format).
To avoid this problem, bulk copy data using field terminators, or fixed-length data fields.