I need a backup software that sends files and folders to a backup folder and compresses them, and does this automatically when the files have been modified (no need to manually tell it to do it).

Are there any good free softwares that do this?

Nothing that'll do it in real-time. The closest to what you want that I can think of is http://www.genie9.com/free_products/free_timeline.aspx (does it hourly)

Now, lots of software can do this on a schedule. I personally favor robocopy for my backups, but backup software I consider "unsvcky" are:

CrashPlan (free version backs up locally/to friends house)
Cobian Backup
Areca
Bonkey

FreeFileSync immediately comes to mind. I haven't used its real time syncing abilities at all but I do use it on a regular basis for other tasks and it is easy to use and good at what it does. It can't do compression, but you could always get another program to do that.

http://sourceforge.net/projects/freefilesync/

I just looked at the component of Freefilesync that they provide for Real Time Sync, and it synchronizes files when:

*all directories become available (e.g. a USB stick is inserted)
*files within these directories or subdirectories are modified

File synchronization is not a backup :nono:

How is it not a backup? Free file sync supports versioning.

I didn't know FFS supported versioning, I was saying that file synchronization is not a backup (because generally syncing tools do just that: sync, and as such don't offer versioning). If it has versioning, then that is probably the closest thing to what the OP is looking for (doesn't offer compression) since it can do it in real-time

Edit: Apparently I downloaded v1 instead of v3, still not certain how that happeend :blink:

Edit2: after fully trying out the correct version, it is a pretty well written program. Out of everything I've seen, though, I think Genie and CrashPlan (the paid version of both) are the closest for what the OP is after. If he is willing to pay for either, they have all the features (otherwise there is the 1 hour limit for Genie and the 24 hour limit for CrashPlan).

The one thing that was bad about FFS for backups is you cannot manage your file versions, though this is true for the free version of Genie too (runs the risk of quickly filling up your disk space if you modify a large file a lot)

Edit3: Eh, FFS has a pretty bad file versioning system IMO after futher playing around with it. it's far too easily overcomed with pointless revisions and the lack of a consolidated rollback really hinders... rolling back (unless you remember when you edited a file, you'll have to go through countless folders until you finally find the right one). Maybe I'm just too picky, but things like that are why syncing software shouldn't be used as backup software. Of course I'm really picky when it comes to backing up, which is why I still do my backups manually (though that's finally going to change with BackupPC and Crashplan this summer)