Very often when working in Model room, I loose the option of selecting vertices, etc. I can see the vertices and edges, but cannot select them anymore. Sometimes it happens when zooming in and other times while working. I have to zoom out and click around to be able to select the things I want. Am I missing something or doing something wrong?

Its a strange behavior... never got something like that.

Are you using the beta?
If the version 7, had no problem for modeling.

I haver version 7.

Have you tried updating your video driver?
Try reinstalling your Carrara again, probably can be corrupted.

Latest update for 7 installed?

I have the latest drivers. Did the reinstall.
Not sure about the latest update. Cannot find any info on that. I have Pro 7.2.0.

Just realised the problems are with imported dae objects. Could this be the reason?

 I had an issue a LONG time ago similar to that with imports. Would let me work on the item for a bit them would just stop, not lock up or anything, just wasn't able to do any work on the object anymore. Only did it on certain items, think they were off some Magazines content CD Found if it's an issue I'd undo a step or 3 of my last edits, export the item as a .obj or 3ds and re import. no more issue... had something to do with the file format or some such thing.. really no clue, but it worked.

hope that helps, if not... no clue  :(

Maybe I have solved it somehow, but not sure. So far I have no problems. I didn't re-import it as obj or 3ds, but changed some values. After import there are very high values (something like 9 digits) in the Translation and Rotation tab on the Motion tab. By locking and unlocking the 6 values, they look now normal. Maybe it was too complicated for Carrara.

Did saving as CAR and re-opening the file fix things in Carrara?

No, that doesn't help. I think I found the problem, but I don"t understand it. Thomllama, I think we had the same problem and the obj did the trick.

This is what is happening. If I create an object in Carrara, a Transform section is created on the Motion tab. But if I import a dae file, some weird things are happening. Besides the Transform section there are also a Translation, Rotation and Scale section created above the normal Transform section with strange and very high values. Whatever I do with the imported object, the 3 weird sections do not respond. The Transform section acts normal. If I export and import as obj, the 3 weird sections are gone and I have only the regular Transform section.

Ok.  Yes, Carrara's OBJ export/import will re-assign a model's scale to 100% and re-assign any rotations/rigging, etc. to 0 degrees. 

Quote - No, that doesn't help. I think I found the problem, but I don"t understand it. Thomllama, I think we had the same problem and the obj did the trick.

Whatever I do with the imported object, the 3 weird sections do not respond. The Transform section acts normal. If I export and import as obj, the 3 weird sections are gone and I have only the regular Transform section.

ya, from what I gather it's something in the coding of the original file that Carrara sees but doesn't really understand.  The file I had was from a Magazine's included CD, I tried a few other programs and they all had the same issue.  when you save as obj it basically traces the exterior surfaces and makes a whole new object from scratch so it fixes it.  Kinda a simplified explanation that was given to me when I had the issue, but it seems to work 99% of the time.

Just found a disadvantage of exporting and importing as obj. Although the amount of polygons stays the same, the object is twice as big. Imported as dae it was 330 kB and the same object after export and import is now 780 kB. So first I'll try changing all values of the weird dae import to zero. If I don't run into problems, I do not use export / import as obj. Probably I can dot that later at any time.