You can stop any bulksheet job, including posting a file, while it is still in process.
In the main menu, click Search > Campaigns > Bulksheets.
Select the check box next to each task that you want to stop.
In the toolbar above the data table, click Stop job.
In the confirmation message, click O.
If you cancel the posting of a bulksheet file after some rows have been posted, then an EF Errors bulksheet is generated with the rows that weren’t posted.