Can I backup or synchronize my files automatically whenever any of them are changed?

Yes. Once you have created your profile, modify it, enable the Expert mode, and navigate to the When -> Changes settings page, then enable the appropriate options. Note that SyncBackSE/Pro must be running to detect changes. Because of this, you may want to configure SyncBackSE/Pro to start automatically whenever you log in to Windows: burger menu (from top left of the main window) > Global settings and tick the option 'Start with Windows'.

This feature is used as a trigger (the profile will scan as normal after being triggered). Bear in mind this will also trigger if Windows notifies SyncBackSE/Pro of a deletion, which may trigger a scan of each side with 'no differences found' [to act on] if the profile is not configured to replicate that deletion. It will also trigger on the creation (etc.) of temporary files. You may be able to Filter such temporary files out from being copied if their name-syntax is fixed or predictable, but you cannot prevent such events triggering a scan.

You may want to set the profile to wait a few seconds after a file has been changed (the option Wait a number of seconds... on the Changes profile settings page). A common problem with running a profile when files are changed is that there is no way for SyncBack to know when a program has finished writing to or updating a file. For example, a video editing program may take several seconds to save the changes you've made to a video. In that case SyncBack will run once it sees the video file being updated, but the video editing program may not have finished saving the file before SyncBack starts copying that file. To avoid these kinds of problems you can configure SyncBack to not start the profile until there have been no changes for a certain number of seconds. For example, a program may need to update many files before it exits. Updating all those files may take several seconds. Let's say you set this profile setting to 5 seconds. If the program updates one file then SyncBack will see the change but won't yet run the profile. The program may then update another file a couple of seconds later. SyncBack will detect the change but still won't run the profile because changes were made less than 5 seconds after the previous change. Once the program has saved all its files, and 5 seconds have passed without any file updates, SyncBack will then run the profile. The following setting defines if the seconds to wait is idle seconds.

SyncBackSE/Pro cannot detect file changes on SAMBA shares (thus/also, NAS devices), FTP servers, email servers, cloud services, devices connected via MTP or devices running SyncBack Touch. Basically, it leverages a Windows function which is restricted to Windows devices, or devices under Windows' direct control, such as flash drives.

Note that this feature is not available in SyncBackFree.