If you’ve run into any instances where it would be useful to synchronize an external drive and your computer or your computer and a server’s files, there are programs that can actually do the synchronization regularly and with different conditions met. Here’s a list of free software that you might evaluate to see if it will do the job for you.
I haven’t used all of these packages but I did a comparison of features and tried out Path Sync and Allway Sync after researching the programs out a little bit. Path Sync worked, but it only handles one directory pair to synchronize at a time. Allway Sync definitely shines brightly as a free application with more features.
You can setup multiple jobs (directory pairs) and then have them (individually) sync based on different conditions like idle time, an external device being plugged into the computer, or using Windows Task Scheduler. You can sync between normal drives (internal hard drives, external hard drives, and USB jump drives), networked drives (UNC paths), FTP server, and Amazon’s S3 service.
One word of warning is that files can be deleted through a synchronization. Be sure to test out your settings on something you have a back-up ready and available.
Get Allway Sync.