If you're getting errors when trying to open Chaos Cosmos from the Corona toolbar, seeing messages like "Cosmos service is not running", or clicking on it does nothing at all, try these solutions one by one:
Solution 1: Restart the Cosmos Service
This is the quickest fix and often solves the problem:
- Click your Windows Start button
- Type "Stop Chaos Cosmos Browser" and click it
- Type "Start Chaos Cosmos Browser" and click it
- Go back to 3ds Max and try clicking the Cosmos icon again
Solution 2: Check if Cosmos Works in Browser
Before continuing, let's check if Cosmos is running properly:
- Open your web browser
- Go to: http://localhost:30305
- If Cosmos opens in the browser, the service is working - the problem is just with the 3ds Max integration
- If it doesn't open, continue with the solutions below
Solution 3: Clean Reinstall Cosmos
If restarting didn't work, try a fresh installation.
Step 1: Uninstall Cosmos
- Go to Windows Settings > Apps
- Find Chaos Cosmos and click Uninstall
Step 2: Delete leftover folders
Delete these folders if they exist:
- C:\Program Files\Common Files\Chaos\Cosmos
- C:\Program Files\Common Files\ChaosGroup\ChaosCosmos
- C:\Program Files\Chaos\Cosmos
- C:\Program Files\Chaos Group\Chaos Cosmos
- C:\Users\[YourUsername]\AppData\Local\Chaos\Cosmos
Note: Replace [YourUsername] with your actual Windows username
Step 3: Download and install Cosmos
- Download the latest version from: https://my.chaos.com/download/build?product=Cosmos+Browser
- Install it
- Restart the Cosmos service (see Solution 1)
Solution 4: Delete Database Files
If Cosmos still won't open, there might be corrupted database files.
- Stop the Cosmos service (see Solution 1)
- Go to: C:\Users\[YourUsername]\AppData\Local\Chaos\Cosmos\DB
- Delete all files that end with .cpkg
- Also delete cpkg.db and cpkg.meta files if you see them
- Start the Cosmos service again
- Open 3ds Max and try the Cosmos icon
Solution 5: Cosmos Window Hidden Off-Screen
Sometimes Cosmos opens but the window is outside your monitor area. This can happen, for example, if you previously used multiple monitors.
- Right-click on your desktop and choose Display settings
- Turn OFF these two options:
- "Remember window locations based on monitor connection"
- "Minimize windows when a monitor is disconnected"
- Change your screen resolution to something different (you can change it back later)
- Close 3ds Max completely
- Reopen 3ds Max and click the Cosmos icon
- If it still doesn't appear, repeat steps 3-5 with a different resolution
Important: You must close and reopen 3ds Max after changing the resolution for this to work.
Solution 6: Cosmos Configuration File Corrupted
In some cases, the Cosmos configuration file can become corrupted, causing the Cosmos window to open off-screen or become invisible. The following steps should resolve this issue:
- Close 3ds Max
- Go to C:\Users\_your_username_\AppData\Local\CoronaRenderer\QCefViewData\
- Rename the file QCefViewBrowserSettings.conf to QCefViewBrowserSettings.conf.BCK - this results in the file being ignored by Cosmos, which triggers the creation of a new file. Another option is simply deleting this file, however in that case it may not be possible to recover it.
- Start 3ds Max
- Check if Cosmos works
Workaround: Use Cosmos from Browser
If none of these solutions work but Cosmos opens in your browser (http://localhost:30305), you can use it directly from there as a temporary workaround:
- Open Cosmos in your browser
- Browse and download the assets you need
However, please also contact Corona support so we can help you further:
- Take a screenshot of any error messages
- Note your 3ds Max and Corona versions
-
Collect and share these logs:
C:\Program Files\Common Files\ChaosGroup\ChaosCosmos\cb.log
C:\Program Files\Common Files\ChaosGroup\ChaosCosmos\config.json
- Contact Chaos support with this information
Remember to restart your computer after trying these fixes - sometimes a simple reboot can solve the problem!