If you get the following message after running the cron import command on the linux/aix/unix system, you can try the following.

Error Message

There were no cron expressions found in cron file. '/var/spool/cron/'


Check that there is a blank line at the top of the crontab file, as if the first command is on the first line then this can cause problems with the import and this then produces the above error, simply add a blank line at the top of the file and run the import again, this should then allow the import to work as expected.