What was the error message you got?
I would suppose that the installer doesn't let you install it to the new location as long as the BIM Server is installed on the C drive, possibly because only one instance of the BIM Server can exist on a machine as it is running as a service and using TCP/IP ports so several instances could mess things up with each other. But this is a guess.
It is possible to Export Projects from the BIM Server, and Creating New Project from importing these exported files.
So a possible workflow would be to Send & Receive all changes in all Projects, save all Projects as PLN or PLA files for backup purposes. Then Export all Projects from the BIM Server, uninstall the BIM Server from C drive, reinstall it on D drive. Then you can recreate the projects in the BIM Server.
In AC14 it is also possible to export/import Users and Roles. IN AC13 this was not possible.
If anyone knows an easier way please chime in.
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