Have a look at the help file that is installed with FreeFileSync: You can access it either by pressing F1 or via the menu bar.
Alternatively an Online Manual is also available.
After you've become comfortable with using FreeFileSync, read chapter Tips and Tricks with many hints that simplify everyday use!
FreeFileSync runs natively on all 32 and 64-bit Windows versions:
Mac OS X
FreeFileSync runs on all recent 64-bit editions of OS X:
FreeFileSync is supported on all major Linux distributions. Official pre-compiled versions are available for:
FreeFileSync imposes no artificial limitations on how many files you can sync. Practically speaking, the only limiting factor for extremely large sync jobs is the amount of free memory available: For each 1 GB of RAM FreeFileSync can synchronize roughly 1.7 million file pairs at a time.
Yes, FreeFileSync may be used in business, commercial, and government environments without cost.
You are permitted to distribute the software subject to the following conditions:
The software must be distributed free of charge and without modification to the contents of the archive. Redistributing this archive with any files added, removed or modified is prohibited. The inclusion of any individual file from this archive in another archive without the prior permission of the author is prohibited.
No, you can safely install a new version of FreeFileSync into a directory that contains an old version. FreeFileSync will recognize the previous installation and clean up thoroughly should you choose to uninstall at a later time.
FreeFileSync is designed for local installation and provides the best user experience in this variant.
In order to support restricted scenarios, FreeFileSync also allows for portable installation on USB memory sticks or external hard drives. However part of FreeFileSync's functionality may not be available in this case: For example it won't be possible to manage FreeFileSync configuration files via context menu in Windows Explorer or start batch runs with a few mouse clicks. Therefore local installation is recommended in general.
The FreeFileSync installer is showing a single advertisement (and only during installation) to help recover part of the software development effort, which is the time and energy invested in application design, implementation and continuous support. Although it's nowhere near enough to allow to focus on FreeFileSync full time, it is more effective than asking for donations only. If nothing else it helps keep the motivation for the project, next to the other big motivation: striving for perfection in software design.
No, FreeFileSync never installs anything without consent. During installation you are provided a single offer screen. If you want to support the FreeFileSync development or find the software that is shown useful, feel free to accept the offer. If not, just decline and nothing other than FreeFileSync will be installed.
If you are doing a silent NSIS installation, no advertisement is shown or installed:
FreeFileSync_7.1_setup.exe /S /D=C:\Program Files\FreeFileSync
A silent installation with Inno Setup is started with:
FreeFileSync_7.1_setup.exe /silent /dir="C:\Program Files\FreeFileSync"
For more info about the advertisement integration, see: installCore Installation Guidelines
Yes, everyone who donates is offered a special version of the FreeFileSync installer without any advertisements.
This is just a small thank-you for supporting the FreeFileSync project!
After donating you are automatically redirected to a page with the download link and a confirmation email is sent, too. The link is valid for a limited time, so make sure to download straightaway.
Note: Some anti-virus programs, most notably Norton by Symantec will falsely flag the installer as dangerous and delete it without providing further info. This is because they use a so-called "reputation-based heuristic", which will simply delete files that are not well known or commonly downloaded. This simple algorithm is expected to fail with the FreeFileSync donor version which is not widely distributed by design. As a workaround you can try to restore the deleted installer or use a smarter anti-virus program.
No, the FreeFileSync installer never contains malware or viruses. Both firewalls and virus scanners work with heuristics
in addition to searching for known virus patterns.
Heuristics are generic algorithms that try to identify malicious behavior by evaluating certain program characteristics
according to their proprietary implementation.
Often it is already sufficient to have a program access the registry or the internet to get this classification. By their very nature
heuristics cannot be exact and frequently lead to false positive detections. Occasionally FreeFileSync is victim of this.
In practice however one can distinguish real malware threats from heuristic alerts: later contain phrases like *gen*, *generic*, *heur*, *heuristic* or *reputation* as part of the threat signature name. Anyway, when in doubt never trust a single anti-virus software and use an online mass virus scanner for comparison.
The best place to get in contact is via the FreeFileSync Forum. This allows for other FreeFileSync users to share their experience and give immediate feedback. A lot of problems have already been discussed and solved, so searching the forum may be the quickest way to get help.
When synchronizing with FreeFileSync and comparing the number of items of the source and target folders with
Windows Explorer, consider the impact of the following settings.
If you still find yourself unable to explain the difference, drill down into specific mismatching folders with both applications until you find an actual file/folder that is handled differently. This should reveal what the problem is.
Copying NTFS permissions is not needed in general and is best left disabled. Go to menu → tools → options and ensure permission copying is unchecked.
If you are an administrator and really need to preserve DACL, SACL, Owner and Group permissions, make sure the FreeFileSync process is running with admin rights.
Certain anti-virus products, for example
Comodo v8, write hidden alternate data streams
to newly created files.
Unfortunately this has the side effect of also setting the file modification time to the current time.
Since this happens after FreeFileSync has copied the files, the next comparison will detect this modification just like any other external change.
To resolve this problem file a bug report on the anti-virus software's support web site, use a different anti-virus software that does not modify files or look for options to disable such features (e.g. disable Comodo's "File Source Tracking").
This depends on how you have set up deletion handling in synchronization settings:
Usually FreeFileSync will generate a mini dump file automatically when it detects a program crash.
This file can then be sent to the FreeFileSync development team for further analysis.
In some situations this will not work correctly, for example if the process is hanging for a long time rather than crashing directly. In this case you can create a dump file manually as follows:
Download the tool Process Explorer and reproduce the crash/hang. Now start Process Explorer and right-click on FreeFileSync_x64.exe (or *_win32.exe if you're on 32-bit Windows), select Create Dump and then Create Full Dump. Next, compress this file with zip or rar and send it to the email shown in FreeFileSync's about dialog.
Download Process Monitor and start it with filter settings reset to default. Now retry the operation with FreeFileSync that you want to trace, switch back to Process Monitor and save the trace as a PML file. You may compress this file with zip or rar and send it to the email shown in FreeFileSync's about dialog.
strace COMMAND_TO_TRACE &> ~/Desktop/trace.txt
sudo dtruss -d COMMAND_TO_TRACE &> ~/Desktop/trace.txt