Hi, There're few possibilites why a TBP file cannot be opened. Have you tried to open any other TBP files? If you're not able to open any TBP files then the issue is most probably in incomplete installation of Tekla BIMsight. So in that case please uninstall your Tekla BIMsight, download the installer package again http://www.teklabimsight.com/downloads.jsp and re-install Tekla BIMsight. On the other hand, if you're able to open some other TBP files but not this one, the TBP file may be corrupted. The file may corrupt for example during the delivery if it is not completely uploaded/downloaded. So if you've received the file, e.g., via email or downloaded the file from a network drive, please ask your colleague to send the file again to rule the possibility of corrupted file. Hope these instructions help and if you're still not able to open the file please let me know and I'll help you further with the issue. BR Heikki