"can you start a new project and render a track to mp4?"
Will do now - why didn't I think of that? hmmmm.....

have you gpu on/off?
off

"card driver should read something like 285.??"
285.62 -- yep cool :)

I'll try creating a new project now .....

just created a new 4:3 poject - dragged in a mp4 file and still wont render - same error as before ....

I have seen your error message when trying to render using a customized template where the settings are outside the possible range.

As V11 sometimes cannot read templates made under V10 correctly, this can be a cause too.

I'm using: Internet 480p 4:3 ... not custom

Been thinking I should Uninstall and reinstall perhaps???

Just uninstalled and reistalled
now the error message is:

An error occurred while creating the media file new trak.mp4
The system is low on memory. May be able to reduce memory usage by closing other applications.

Still wont render .....

try rendering a track at a time. maybe bad media on one of your tracks (yes, i know they were created in vegas, but you never know...)

@rmcn: I tried to render the same template just to see if it were a general issue - but here it went without problems and I rendered 1 minute of the timeline in some 26 seconds.
The GPU usage was some 50-60 percent doing this.

Something else I’ve noticed:

If I open SV from the Start Menu, I get this message:
The last session did not complete properly.
You can restore the autosaved version of the project that was opened,
but you should use the Save As command to rename it immediately.
Would you like to restore the autosaved project? YES/NO

But if I open any project via the .Veg file this message doesn’t come up.
the project (any project) will play fine in the editor but wont render.

If I choose YES (to restore the auto saved project), then a really old version of the project appears in the editor. Ok, whatever – so I “save as” but it still wont render.

I tried creating a new project with only one jpg file on one video track = still wont render.

Sorry, I’m new to Vegas and I’ve got no idea whats going on here ….

I used to have the same problem rendering MP4 files when I had an old ATI video card. I believe the problem may be caused because Pro 11 uses GPU accelaration to create MP4 files and it doesn't work with all GPU/diver combinations. I use a GTX 570 and the problem has disappeared.

I used to get around the problem by rendering to WMV files instead of MP4.

Thanks you so much NicolSD !!!!!

I just successfully rendered to wmv file type.
Wasn’t sure which *.wmv to choose so I
chose “3 Mbps Video” from the Windows Media Video V11 selections.

You're a life saver

By the way the file size produced (3:22 length video) is about 76 Mb (WMV)
whereas previously using MP4 (before Vegas refused to work anymore)
the file size was about 22 Mb - Hey, but I'm not complaining :) :) :)

Thanks again for all your help

I just figured out how to render MP4 (problem solved)
I changed “Encode mode” to “Render using CPU only" instead of "Automatic" GPU selection and I can render MP4 again - cool awesome

Hope this helps if anyone else comes across this 'problem'

Cheers forum :)