Untraceable error importing Huge dataset with SQLCMD
It's possible that you hit SQL's size limit for batch size. Check out https://msdn.microsoft.com/en-us/library/ms143432.aspx.

If your file is just line after line of INSERT INTO [Table] (field, field) VALUES (value, value); then you have some better options than splitting the file.


Add GO statements every few thousand lines, which helps break things up into smaller batches.
Use Powershell or another language to create a stream reader send every line to sqlcmd. Chrissy LeMaire created a great script to do this for CSV files that you could use for inspiration: https://gallery.technet.microsoft.com/scriptcenter/Import-Large-CSVs-into-SQL-216223d9. I've used a variation on this method to import files with a half-million INSERT statements in less than a minute.