How do you enable sync-by-wire?

I’m trying out Bonjour-based sync. I have an M2 MacBook running macOS 13.4 and an iPad Pro 12.9" (generation from 2018)

On the iPad, I’ve removed all databases, then set up Bonjour sync over wifi. It works, but no doubt owing to the size of the databases involved, it has been extremely slow to download the databases for the initial sync.

According to this blog post from 2020, it should be possible to do Bonjour sync over a USB connection between the iPad and the Mac. So I connected them using a high-quality USB-C cable (directly, without a USB hub between them), turned off wifi on the iPad, and … nothing. The little cloud icon in the bottom row of the DEVONthink to Go app screen is grayed out, suggesting it cannot “see” the network location for the Bonjour server. If I go to the DTTG app preferences and tap on “Locations” (where the tap text is “Local network”), in the list of locations, the one for the Mac is visible but the text underneath it says “(Offline)”.

I’ve read the tips in the Bonjour Simplified article from 2021 and followed the instructions. I have also tried the following:

  1. force-quit and restart DTTG (with wifi off and the cable connected)
  2. force-restart the iPad
  3. tried multiple USB-C cables
  4. turned off the network firewall in the Mac network preferences
  5. waited, in case some discovery process on either/both devices needed to scan and discover each other

What else do I need to check?

I don’t know how to use a wire to connect, sorry. I rely on WiFi, and yes, initial sync will take the time it takes.

Just curious. Why did you remove all the databases? Assuming the same databases as in the new connection method, would have avoided the first-sync time and you left them in place.

Persistent sync issues using the CloudKit method left at least one database persistently out of sync. I’ve seen that problem before and a combination of cleaning the sync store (using the master copy on the Mac) and deleting+redownloading the databases on iOS devices has cleared that up in the past.

This time around, since I was doing all that anyway, it seemed like an opportunity to try Bonjour.

First of all, the USB-C cable needs to support data transfer, not just power. This is not easily identified but generally a thicker cable is often capable of both.

  • If you connect the devices via cable and the server is shown as offline, try quitting and relaunching both apps.
  • If that doesn’t resolve it, remove the Bonjour location and add it again.

Currently, I have no WiFi on my iPad and am connected to the Mac, USB-C to USB-C. Changes made in either app are syncing nicely.

but no doubt owing to the size of the databases involved, it has been extremely slow to download the databases for the initial sync.

You need to make sure the mobile device is awake and DEVONthink To Go frontmost during the initial import. Background App Refresh isn’t under our control and it’s insufficient for the first pull of a database, excpet for very small ones.