Mac: fails to connect to devices after a few hours

Hi there

Very new to this, but here goes.

I installed Syncthing 0.11.22 using Homebrew on my Mac, following the auto startup guide in the documentation (adding the plist to the Launch Demon to get it starting automatically). So far so good. I connect another device of mine (a Windows 7 machine running 0.11.22 as well), works like a charm: The folders are syncing perfectly.

A few hours go by, and I see that my Windows machine is “Disconnected” in the web GUI of my Mac. Last seen: 4 hours ago, back when things were working fine. I decided to check for an upgrade from the console, but get this error:

$ syncthing -upgrade-check

FATAL: Upgrade: upgrade unsupported


$ syncthing -upgrade

FATAL: Upgrade: upgrade unsupported

Okay, decided to shut Syncthing down:

$ syncthing -no-restart

INFO: Database block cache capacity 65536 KiB

FATAL: Cannot open database: resource temporarily unavailable - Is another copy of Syncthing already running?

Okay. My Mac needed a reformatting anyway, so reformatted and reinstalled Mac OS. Installed Homebrew and Syncthing, now version 0.11.23. Set up my device, everything works. A few hours later, the same thing happens: Can’t connect to the device, and it seems that Syncthing insists that multiple copies are running.

How do I prevent this from happening? Is this a result of using Homebrew to install syncthing? (Perhaps multiple Launch Demons loading syncthing at the same time?)

I can confirm that my Windows machine is working 100% - it talks happily to other Windows devices on my network. It’s definitely this Mac that fails to connect after a while, losing connection to all other devices.


If you install Syncthing using homebrew, you must upgrade it using homebrew. -upgrade and friends won’t work. Run brew update and brew upgrade syncthing instead.

I’m not sure what you were trying to achieve by running syncthing -no-restart: that will run a second copy of Syncthing (that second copy won’t have a monitor process either, which is almost certainly not what you want). If you want to shut Syncthing down, either use the Actions -> Shutdown option from the web GUI, or use launchctl unload path/to/syncthings/plist.

Thanks for the quick reply!

Okay, I was mistakenly under the impression that -no-restart was the method to shut syncthing down by command line. Doh!

Still can’t get my Mac to connect after a few hours of installing and setting up Syncthing though - will fiddle with it and respond.

Is the mac on the same network, or is it connecting across the internet. Do you have port forwarding setup if its over the internet, or at least UPnP support by your router?