Cosmos browser cannot register the host application

Corona Corona for Cinema 4D Issues
1

Cosmos browser cannot register the host application.

For now better not to update to the latest C4D2025. I tried the previous solution that worked for C4D2024 and CR13 by uninstalling Cosmos and deleting Cosmos Library files. It does no longer for C4D 2025.

OSX most recent
C4D 2025
CR most recent build 13

Cosmos browser stalls.jpeg
Cosmos browser stalls.jpeg1234×2046 176 KB

2

Don’t forget to say which build specifically, not “most recent” (as sometimes what people think is most recent is not actually the most recent). Also, is working ok on my machine on Windows so may be a macOS specific thing?

PS though in this case there is only the one build that works with C4D 2025, but, it’s a good habit to get into naming it and not saying most recent :smiley:

3

OSX 14.6.1 (23G93)
corona-13-c4d-daily-2024-08-28
C4D 2025.0.0

Problem can not be solved by the instructions in the popup that starts when Cosmos does not load : Cosmos browser cannot register the host application.

Cosmos browser stalls.jpeg
Cosmos browser stalls.jpeg1234×2046 176 KB

4

I looked at the installer and customize and noticed that Cosmos installs zero bytes. Might that be the problem with the installer of the latest build corona-13-c4d-daily-2024-08-28-mac. ?

Zero bytes.jpeg
Zero bytes.jpeg1226×874 159 KB

5

Is it just me ? Anyone has the same problem with C4D 2025 and OSX 14.6.1 and CR13 ?

6

Hello, same here after updating Cosmos:
Cosmos Browser cannot register the host application

Cinema 4d 2025.0.2
Corona 12 Update 1
Mac OS Sonoma 14.5
Apple M1 Ultra

Help me please !!

7

3 hours later the support is not responding, nothing moves.
this is the last time I click on update cosmos !

8

There is an update bug in cosmos. There is a workaround however.
Once you click update in Cosmos, Cosmos stalls and at the same time the installer appears on your desktop. Go from C4D to your desktop and use the installer manually. After that, Cosmos is installed and works again.
Don’t know why Chaos does not provide these instructions since this problem is there already for a while.

9

1. The Cosmos Browser service has not been started or has not been launched as an administrator. Please go to Task Manager, switch to Details, and check if cbservice.exe exists.
2. You have not installed C:\Program Files\Chaos\UnifiedLogin\ula.exe, so the message “Host application failed to register to Cosmos Browser” keeps popping up.
3. Check the firewall and delete the cpkg.db cache file at C:\Users\Administrator\AppData\Local\Chaos\Cosmos\DB\cpkg.db. Please refer to the official instructions for details.

10

Hi everyone,

Sorry for the trouble with the Cosmos Browser registration issue. Since this thread has gathered a mix of macOS and Windows reports with slightly different root causes, here is a consolidated set of steps that should cover most cases. Please try them in order for your platform.

Official troubleshooting reference: Troubleshooting

On macOS:

  1. Quit the host application (C4D, 3ds Max, Maya, etc.).
  2. Delete the Cosmos DB folder contents at:
    /Users//Library/Application Support/Chaos/Cosmos/DB
  3. Open Activity Monitor, search for “cbservice”, and force quit it. It will restart automatically.
  4. Verify the service is running by opening http://localhost:30305/ in a browser. If that page loads, the service itself is fine and the problem is only with the host-app connection - restarting the host app usually resolves it at that point.
  5. Check that no firewall or antivirus is blocking local communication between Cosmos and the host app.
  6. If the issue persists, do a clean reinstall. Uninstall Cosmos, then remove these folders before reinstalling from https://my.chaos.com:
    /Library/Application Support/Chaos/Cosmos
    /Library/Chaos/Cosmos
    /Users//Library/Application Support/Chaos/Cosmos

On Windows:

  1. Open Task Manager, go to the Details tab, and confirm the Cosmos Browser service process is running. If not, start Cosmos and check again.
  2. Delete the cache database folder at:
    C:\Users<your-username>\AppData\Local\Chaos\Cosmos\DB
  3. Check firewall and antivirus settings to ensure nothing is blocking localhost communication on ports 30305 and 30306.
  4. Verify by opening http://localhost:30305/ in a browser.
  5. If the issue persists, do a clean reinstall. Uninstall Cosmos, then remove these folders before reinstalling from https://my.chaos.com:
    C:\Program Files\Common Files\ChaosGroup\ChaosCosmos
    C:\Program Files\Chaos\Cosmos
    C:\Program Files\Chaos\UnifiedLogin
    C:\Users<your-username>\AppData\Local\Chaos\Cosmos

If none of the above resolves it, please collect the Cosmos log files following this article:

And submit a ticket with the log attached here:
https://support.chaos.com/hc/en-us/requests/new

That way we can look at the specific registration failure on your machine and track it properly on our side.