Hi Olivier,
It sounds like your colleagues have managed to get multiple versions of import plugins in their machine. And Trimble Connect Desktop 1.6 is incompatible with some older versions of IFC plugin.
To solve this, they need to follow these steps:
1. Uninstall Trimble Connect Desktop
2. Uninstall Tekla BIMsight
3. Uninstall all plugins, they start either "Trimble Solutions ImportSDK" or "Tekla Model Sharing Foundation"
4. Navigate to following folders and clear them:
C:\Program Files\Trimble Solutions\ImportSDK
C:\Program Files (x86)\Tekla\Model Sharing Foundation
5. Open regedit.exe and navigate to following path and remove all plugins that are listed there:
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Tekla Corporation\Model Sharing Foundation\plugins
6. Install Tekla BIMsight if that is needed
7. Install Trimble Connect Desktop
Now all IFC models should work again. Trimble Connect Desktop and Tekla BIMsight use the same plugins, but Tekla BIMsight has older versions, thus it's needed to install first. And try to make sure that installations of the software and their updates is done by same user. If IT admin does the installation, they need to do the updates also.
Hopefully this helps. Please ask, if you need more info on some steps.
Best regards,
Marko Myllymaa