Hi everyone,

CST Studio Suite 2026 was working normally until yesterday. Today, when launching CST from the desktop, I started receiving the following error:

Unable to retrieve NAMED_USER

When launching CST from the 3DEXPERIENCE website instead, I receive:

Failed to get login ticket for (2147418113)

The unusual part is that, on the same computer, CST starts normally from another Windows user profile using the exact same 3DEXPERIENCE/CST account, password and two-factor authentication.

The browser login and two-factor authentication complete successfully. The problem appears only when CST requests the final login/licence ticket.

My environment:

• CST Studio Suite 2026
• 3DEXPERIENCE R2026x HotFix 5
• Windows 11 25H2
• Google Chrome
• 3DEXPERIENCE cloud platform

I have already tried the following:

• Restarted Windows and the 3DEXPERIENCE Launcher.
• Signed out and back into the 3DEXPERIENCE platform.
• Cleared all Chrome cookies and site data related to 3dexperience.3ds.com and 3ds.com.
• Tested from a Chrome Incognito window.
• Opened 3DSpace and the Common Space before launching CST from the Compass.

• Backed up and reset:

  %APPDATA%\\DassaultSystemes\\CATSettings

• Repaired the 3DEXPERIENCE Launcher installation.
• Checked the Launcher diagnostics. All tests pass:
  • service installed and running;
  • registry valid;
  • current user has read/write permissions;
  • connection to http://127.0.0.1:20250 successful.
• Confirmed that the following roles are assigned:
  • 3DSwymer;
  • Collaborative Industry Innovator;
  • All Physics Analyst;
  • Electromagnetics Engineer.
• Confirmed that the user is a member of the Common Space as Leader & Owner.
• Confirmed that the correct tenant and platform URLs are passed to CST.
• Confirmed that no other Windows users or CST sessions are connected.
• Reviewed the generated session information. A CAS/transient authentication ticket is created and two-factor authentication is validated, but CST still does not receive the final NAMED_USER ticket.
• Confirmed that the Launcher process ends normally without a crash; CST itself does not start.

This issue has occasionally happened before and then resolved itself, but this time it is persisting.

Has anyone experienced this exact behaviour, especially when the same 3DEXPERIENCE account works from another Windows profile on the same computer?

Is there another per-user authentication cache or credential store used by SMAPowerByLauncher or the CST 3DEXPERIENCE connector, in addition to Chrome data and CATSettings? Alternatively, is there a way to reset the NAMED_USER session or role synchronisation on the 3DEXPERIENCE server?

Any suggestions would be greatly appreciated.