For me what happened was that I work for about 6 hours in a project with 7 pointclouds imported. It worked fine until suddenly TBC crashed, it just closed without any crash-report or anything, and after that the imported pointclouds contained 0 points. I then downloaded an old version of the project from Dropbox. In this version the pointclouds contain points but nothing shows. I'm not super-excited to redo all the work...