When I open Chaos Cosmos in Rhino, the page doesn’t load and looks like this:
Has anyone run into this issue? It was working fine just yesterday.
Let me know if you have a solution to this, thanks.
Hi Kevin,
We’re already aware of the issue and the fix will be deployed soon. Host app restart (Rhino) may be required. Will keep you updated.
Hi, I have the same problem in 3dsmax. I installed the new version of vray but the problem is still there.
Hi all,
We deployed a fix. You may have to restart your host app (Max, Rhino, etc.).
Please let us know if the problem is gone or not.
Thank you and apologies!
Yeh, I had to close my apps, go to windows start, and type cosmos…bring up a “stop cosmos” option. Then search for cosmos again and choose “start”. Reopen Maya / Max. Works for me.
It’s ok for me, thank you very much!
Cosmos stop/start is not required, just restart of the host app. Thanks for confirming!
Confirmed, it’s working for Rhino as well now.
Just restarted the PC and app, thank you.
@hristo_chakarov
Hi,
I think I have a similar problem, can you see my post Chaos Cosmos Browser Failed to load - Chaos Forums
and let me know?
I submitted a ticket 447321.
Last response was “…Cosmos is very sensitive to any restrictions, but it is a stable application, and the reason for not working is local. Please troubleshoot what may change the settings of BitLocker encryption, and just change it…”
I can’t change Windows BitLocker.
Also, the issue with Cosmos recently started, and I have been using BitLocker for 2+ years on this system, and 5+ years on my prior system with no issues.
I have uninstalled & reinstalled Cosmos 2025.11.27 12/10/2025 (install date).
I start my computer each morning (I turn it off at night), C: boots, then I use a password to unlock D: BitLocker protected drive, where Cosmos library is stored.
If I start Rhino, I get the error as noted in my other post. then exit rhino, stop cosmos browser, start cosmos browser, start Rhino, it is fine. Until the next day or a reboot.
I have been doing this instead: after boot & unlock D:, I stop cosmos browser, then start cosmos browser, then start Rhino, Cosmos browser is fine. Until reboot or next day start up.
let me know if you need more information.
Thank you,
Glenn
Hey there @glennco ,
I’m already familiar with your case, as our support team contacted us already.
You are saying that the issue started recently. May I ask you to downgrade your Cosmos Browser to version 2025.11.06 and see if the issue will persist? Here’s how to do that:
- Uninstall Cosmos from Start Menu –> Uninstall Cosmos Browser;
- Delete all files in %LOCALAPPDATA%\Chaos\Cosmos\DB
- Download and install version 2025.11.06 (you will have to login with your Chaos account)
- Open Cosmos Browser and log in
Restart your computer few times and let us know if the problem persists.
@hristo_chakarov
Thank you for the reply.
I will downgrade in a few days after I complete several client projects.
Are there any risks to downgrading, could that cause any problems with Rhino files using the later Cosmos Browser version?
Another thought, could there be any issues with the latest Cosmos Browser start.bat , that it is missing something about locked drive and wait for drive to be unlocked before starting (C: is my system drive, D: is my data drive & Cosmos library location)?
Or is that why you want to try the downgrade?
Glenn
p.s. I"m UTC-7 & being self-employed I’ll be working throughout the Holidays, so I might not get to this issue until then.
Hey glennco,
Are there any risks to downgrading
No. There are no major changes between the latest version and this one 2025.11.06 .
could that cause any problems with Rhino files using the later Cosmos Browser version?
No. Since the two versions are very close in time, there are no major changes in the APIs.
Another thought, could there be any issues with the latest Cosmos Browser start.bat , that it is missing something about locked drive and wait for drive to be unlocked before starting (C: is my system drive, D: is my data drive & Cosmos library location)?
No. We released a fix after version 2025.11.06, which could be causing the issue on your end. In other words, Cosmos worked for you in the past due to a bug that was fixed recently. If that’s the case, we will think of a workaround for your case.
Looking forward to hearing from you.
@hristo_chakarov
This morning Cosmos browser works as intended. (I think the same thing happened yesterday too).
I made no changes to Cosmos or my PC.
I booted, started Rhino, Cosmos browser no error.
I did not stop/start, or downgrade. I’m still on Chaos Cosmos • Build: 2025.12.17-607150
I’ll monitor for a few more boot cycles & let you know.
For now, everything is back to normal (on it’s own).
Thanks,
Glenn
After login, did you immediately unlocked D drive?
@hristo_chakarov
yes, within a couple of minutes. Before doing anything.
Same way I always power-on my PC.
power button (I turn power off at night), enter password for W11 (c: is not BitLocker protected), then unlock d: with password, then start working.
Glenn
Then it could be a timing issue, that was always there, but sometimes you manage to unlock D before Cosmos Browser starts, the other time it starts before you unlock the drive and enters Troubleshooting mode. If that’s the case, when you hit it, simply restarting Cosmos Browser (Stop, then Start, from Start Menu) should work.
@hristo_chakarov
Thanks for the idea.
This morning, I powered on computer, entered password for W11, waited 5minutes, unlocked D:, waited 5minutes, opened Rhino, Cosmos browser working as expected.
Intermittent problems are so frustrating.
Thanks for your help,
It seems to have corrected itself; I will post here if the problem occurs again.
Glenn