Looooonnnngg sync time between mobile and fixed clients

Sometimes the windows tablets we take in the field take hours to sync over cellular.

Sometimes it’s literally hours, but sometimes minutes. The “pause devices which connect over a metered network” is unchecked in SyncTrayzor.

Is there a setting we can change to help this?

Can you elaborate a bit more about the configuration? What kind of hardware do you use exactly?

You’ve mentioned Windows tablets specifically, and those come with a feature called Modern Standby (see https://learn.microsoft.com/windows-hardware/design/device-experiences/modern-standby) enabled by default. This is a very nice feature that reduces idle battery drain to minimum, but the problem is that in order to do so, it blocks all “unnecessary” background activity, which includes Syncthing. In other words, Syncthing will be suspended when the device is in idle state, meaning that it will still stay in RAM, but it won’t be able to do anything until you exit the idle state.

Of course, the problem may be something completely different, but with the limited information and seeing “Windows tablets” mentioned (which I’ve got quite a bit of personal experience with), Modern Standby was the first thing that came to my mind.