SyncBack

Backup software mostly asks you to trust it and then hides what it did. SyncBack takes the opposite approach, building each job as a profile where you decide what happens in every situation the two folders can be in, and then showing you the result.

SyncBack profiles come in the three shapes the job actually has, meaning copying in one direction, keeping two places matched, or making a destination identical to a source.

Before any of that, there is one difference between the free version and the paid ones that decides whether the free one will back up the files you care most about.

The free version cannot copy files that are in use

Here is the SyncBack limitation the maker states plainly and the description on any download page will not.

A program that is writing to a file locks it so nothing else can interfere. That is sensible behaviour and it means the file cannot be copied while the program is running.

The free version cannot get past that. The maker’s own guidance is that you either exclude those files or close the programs holding them before the backup runs.

The consequence is sharper than it sounds, because the files most likely to be locked are the ones you most want copied. A mail client’s data file is locked the whole time the client is open. Databases are locked while anything is using them. Accounting files, project files and anything with a program sitting on it are all in the same position.

So a free backup running while you work quietly skips exactly the material you would miss.

What the paid versions do about it

The paid SyncBack mechanism deserves understanding, since it is not the software’s own invention.

The system provides a snapshot facility that captures a consistent point-in-time copy of a volume, including files currently open. The paid versions use it, which is how they back up a mail file or a database while it is in use without asking you to close anything.

That capability is the main line between the tiers rather than any list of extra features. Somebody backing up documents overnight on a machine nobody is using may never notice, and somebody backing up a working machine during the day will notice immediately.

Two practical notes from the maker’s own troubleshooting. The snapshot facility belongs to the system rather than to this software, so failures appear in the log as system errors rather than as faults here. And desktop search programs have been documented interfering with the copying of locked files, which is an obscure cause worth remembering.

You decide what happens in each case

This is the SyncBack design decision that separates it from simpler tools, and it addresses the danger those tools carry.

Most synchronisation asks for a direction and then behaves accordingly, which is how people empty the wrong folder. Here each situation is configured separately, meaning what to do when a file was changed on one side, when it was deleted, when it is new, and when nothing changed.

That granularity is the point. Deleting on the destination because it was deleted on the source is a choice you make explicitly for that profile, rather than a consequence of picking the wrong word in a menu.

It is also more to think about, and anybody wanting a folder comparison that shows the differences before acting with fewer decisions will find that more direct.

Versioning is the other paid line

The SyncBack capability people discover they needed after the fact.

Without versioning, a backup holds the current state. A file corrupted or wrongly edited yesterday, backed up overnight, has overwritten the good copy, and the backup now faithfully preserves the damage.

Versioning keeps previous copies, so the state from before the mistake remains recoverable. That is the difference between a backup that protects against losing a drive and one that protects against losing a file.

It belongs to the paid tiers, which is a reasonable line to draw and one to know about before relying on the free version for anything you edit frequently.

For backups that are versioned, compressed, encrypted by design rather than as a tier, Duplicati approaches the problem from that direction.

Where the free version is enough

Being fair, because free SyncBack is unusually complete for what it covers.

Copying personal files to another drive, an external disk or network storage works properly, with scheduling, filtering and the same detailed control over what happens in each situation.

There is no registration, no email address requested and no data collected, which in this category is worth stating rather than assuming.

So the honest position is that the free version is a real backup tool with one significant gap. If nothing you back up is ever open while the backup runs, that gap does not exist for you.

Scheduling and knowing whether it worked

The SyncBack part people set up once and never check, which is where backups fail silently.

Profiles run on a schedule through a service that watches them and reports problems rather than leaving a failed job sitting unnoticed in a log nobody opens.

That matters more than any feature in the list. A backup nobody verifies is a hope rather than a plan, and being told when a run failed is the difference between the two.

The logs record what was copied, what was skipped and why, which is where you find out that the free version passed over your mail file every night for a year.

For keeping folders matched between machines continuously rather than on a schedule, Resilio Sync works in both directions as changes happen.

Conclusion

SyncBack is a properly built backup tool whose free version is more capable than most paid ones, with a single gap that matters more than its size suggests. Files held open by a running program are skipped, and those are frequently the files worth backing up.

Work out whether that describes your situation before deciding. A machine backing up documents overnight while nobody uses it loses nothing to that limitation. A machine backing up during the working day, with a mail client open and a database in use, is quietly missing exactly the material a backup exists to protect.