Hi Garystan,
If I have understood correctly you are still getting the render error on the models created BEFORE you reinstalled the program, while the one created since is OK - is that right?
The render error is caused by the rendering engine having difficulty with one particular element - resumably a light. If you can find the offending light and delete it you will probably find it will render OK.
First try turning off all the lights in the view filter and render. It may give a useless dark render but, if it completes without the error message, you know it is a light that is the problem. Now you need to find which. If you only have a few lights save a test version of the model and then delete one at a time and render in between to see if it works. If you have a lot of lights delete half and then try. If it works you know the offending light is in the group deleted.
If turning off all the lights and rendering still produces the error, then the problem is in some other element. It is a process of elimination unfortunately. Turn off appliances and render - if OK, turn them on and turn off something else and try again and repeat until it works. Whatever groups of elements is off when it renders OK is where the offending element is. Again all you can do is delete bits to find it.
The error does not necessarily mean that the light (or whever it proves to be) is faulty in itself, but elements can react with each other to cause unexpected effects. One time I had accidentally installed a glass door cabinet twice in the same space (Collision detection was off). The result was all the glass in all the windows, doors etc etc glowed brightly as is they were lights. When I found it I deleted the extra cabinet and everything was back to normal !
In your case the element causing the rendering to fail may just be the way the light (if it is a light) is placed. One could have accidentally been placed or partially inside a wall for example. Sometimes a break in a wall, or odd fragments of wall left behind in an intersection when walls have been changed, can cause a corruption and result in a render error or program crash. If your render tests work when the walls are turned off, then you need to examine all the wall joins, and even the straight walls, to make sure there are no extra segments in the wall. Selecting a wall should result in a blue marker in the middle with a red and green at each end. If one of the end markers is anywhere other than the end of the wall, then there is a break and a potential problem. Delete one section and drag the free end of the remaining section of wall through to make the wall join again.
If your initial tests do not find anything, post the file here or email it to me if you prefer and I will have a look at it for you. My email is alches(AT)iinet.net.au (replace the (AT) with @ of course). If you have done a lot of work on it that would be a better option than starting all over again.
The render you have posted looks very good. Was that Basic or Advanced? Generally Basic works best for outside views as the Radiosity mode of Advanced relies on light bouncing around inside a room, which does not happen 'outside'. Do you get the render error on Basic or Advanced (or both)? I notice that the trees in the background image look like Australian Eucalypts - are they?
Allan
