serpentine 5 Started with your model post , changed to SU7, quick check showed 78 broken lines , 39 stray lines. Flatten it to remove any question about planer. If you select various faces in the model you will see areas where they are selected and they should not based on wall etc. Some are caused by coplanar lines , duplicate faces etc. Where these errors came from? Probably as TIG stated but they can also be caused by you as you make the model. Make sure you spend some time on the video tuts so you under stand inferenceing use. Once you get to this model level it can get difficult to correct so slow down and hurry up is the best approach. There are plugins that can help you trouble shoot but best to under stand the SU basic capability first.

Yes , I did . The solution is to change the laptop only . Best wishes .

A reboot! - that usually works... If it doesn't [which rarely happens - just now and again] there are free tools - 'unlock[er]' - that will force the system to release the file that's messed up - although sometimes it might require a restart anyway... Be wary as many 'unlock[er]' related downloads are loaded with Malware - but this one seems OK http://emcosoftware.com/products/unlock-it/download.php