It’s good to hear you’ve had luck on all the other OS’s, hopefully MacOS / OSX won’t prove too much of a hurdle for you. 
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Yes - Duplicati uses .NET and Mono is we get .NET on Linux and MacOS
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It all gets installed together, but there isn’t a “Run with windows” type checkbox to make it auto-start. You’ll need to either set up per-user startup items via the standard MacOS System Preferences -> Users & Groups -> Login Items (tab) interface OR using a plist file as described here: MacOS / OSX service installation
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No major differences - it feels the same with paths in the Linux style
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The build-in scheduler works the same, including how it has to be running (either in server or TrayIcon mode) for the schedule to work. If you do NOT want it running all the time, you could use an OS based scheduler to trigger backup via command-line
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I personally haven’t had much time to test out a MacOS install. I got it installed and running as a server / service in under 30 min. However, I have had permission issues accessing content across multiple user accounts, but there’s only one ACTIVE user so it hasn’t been high on my priority to figure out
And thanks for reminding me - I actually meant to put together a #howto for the Mac but only got as far as the linked topic above.