Alright, that said, sometimes all you want to do is sync files from one folder to another; fast and simple and with a minimum of headache, whether files on your Mac only, or between Macs, or to an external storage device. Here’s an easier than easy way and it’s free.
Sync Me Baby
What would you expect a Mac app named SyncTwoFolders to do? Well, sync one folder to another, right? And you would be correct. That’s what this free Mac utility does. Not much more, but you get what you pay for. SyncTwoFolders uses the time honored Source and Destination user interface. Select the source folder of files from your Mac, wherever they are.
Then, select the Target folder or Destination to sync to. That can be another folder on your Mac, an attached USB thumb drive or stick, or a connected external USB device, or even another Mac. That alone makes it easy to copy files from one source location to a target destination, but SyncTwoFolders has a few extra tricks, including options for the Synchronization Mode to keep files synced up between two sources.
As an example, you can choose names or extensions to ignore during the sync, sync up icons, sync both folders of files, or replace files on the target.
SyncTwoFolders is sufficiently robust with features to process Mac Packages (the Photos library is a Package folder), run multiple copy protocols (Xojo, AppleScript Finder, Unix shell copy), and batch sync multiple folders every x-number of minutes.
That makes the app a good choice to sync up folders of files you’re using at the moment to avoid losing a file during Time Machine’s one hour black hole.
For Preference and settings junkies, SyncTwoFolders has the obvious ones, and a few others, including a sync with Mac volumes, an option to movie items to the Trash, or use a specific folder.
Not bad for free, right? OK, not quite free. SyncTwoFolders is donationware. If you like using it, and you might, then consider an appropriate donation. Maybe a donation here and there will help the app developer overcome the security issues that macOS Sierra throws up before it can be installed. There’s no Apple security certificate so you have a few hoops to jump through to get it installed.
As always, caveat emptor.