You set up a new Galaxy phone, restored everything with Smart Switch, and now Google Messages will not connect to RCS — often with error code 3100 on screen. Your chats fall back to plain SMS, group threads break, and typing indicators and read receipts stop working. Reports of this started piling up this week, and Google has now acknowledged it, though not with a fix that reliably works.
Why Google Messages RCS breaks after Smart Switch
The common thread in every report is a device migration. The case that surfaced the problem involved a user moving from a Galaxy Z Fold 6 to a Galaxy Z Fold 8 using Samsung’s Smart Switch, after which Google Messages could no longer register with the RCS service. A Google support representative responding publicly attributed it to “corrupted cache files” carried across during the transfer, as quoted by Android Police.
Two caveats you should hold on to before you start troubleshooting. First, Google’s response arrived in a user forum thread rather than a support bulletin, so this is Google staff talking informally, not a documented advisory with a stated scope or a fix timeline. Second, nobody has said how widespread this is. If your RCS is working, there is nothing here you need to do.
It is worth being clear about what actually fails. RCS registration is tied to your phone number through the Carrier Services component, not to Google Messages alone. When that registration is in a bad state, reinstalling Messages achieves nothing — which is why the steps below target Carrier Services instead.
How to fix RCS error 3100 in Google Messages
This is the sequence Google’s representative suggested. Work through it in order, because the reset only takes effect if RCS is switched off before you clear the Carrier Services data.
- Update Google Messages. Open the Play Store, search for Google Messages, and install any pending update before touching anything else.
- Turn RCS off. In Google Messages, tap your profile picture, then Messages settings > RCS chats, and turn off RCS chats.
- Clear Carrier Services data. Go to Settings > Apps > See all apps > Carrier Services > Storage & cache, and choose Clear storage (labelled Clear data on some builds). On One UI the path is Settings > Apps > Carrier Services > Storage > Clear data; you may need to enable Show system apps from the menu to see it at all.
- Restart the phone. A full reboot, not just closing the app.
- Turn RCS back on. Return to RCS chats and enable it. Registration can take a few minutes to complete.
If that does not work
Be prepared for it not to. The user whose report started this did not get a working result from that procedure, and Android Authority notes that several remedies are circulating with mixed success. That is the honest state of things right now.
The workaround people are having more luck with is avoiding the migration path altogether: set the new phone up as a fresh device rather than restoring through Smart Switch, then move your apps and files across manually. It costs an evening. It also means you are the one deciding what comes over, which is not the worst outcome — our guide to moving data to a new phone covers doing that without a vendor migration tool.
One more precaution if you have not switched yet: turn RCS chats off on your old phone before you retire it, then enable it on the new one once setup is finished. Leaving a number registered to a device you no longer use is the same trap that stranded people’s texts when they moved off iMessage years ago, and it is a thirty-second job to avoid.
If none of this clears it, RCS will re-register on its own once Google pushes a server-side or Carrier Services fix — the safest move in the meantime is to leave RCS off rather than repeatedly toggling it, so your messages at least fall back to SMS predictably instead of dropping into a half-registered state.
Sources: Android Authority, Android Police
