May be a dumb question, but - how long have you waited? I had a biggish project recently (for a friend) - about 500 clips to load every startup. Vegas would ALWAYS get to about sixty-something percent and then "not responding". If I ignored it for long enough it always came good.
As a rough guide, it took about 15 mins to load. This is from source material on an external USB2 HDD, with edits, fades, audio, music etc. (HP Laptop, I7 2GHz CPU, 8GB RAM).
One thing I have noticed with V12 - where previous editions would "die" with the white screen, this edition seems to recover spontaneously if given time.
Of course if it just doesn't happen at all you have a real problem. Not a clue I'm sorry.

Thanks Atom & Ron,

its only this one project - and I cant split it because I can't open it.

V12 doesnt tell me its not responding - it tells me its stopped working. When I close the error screen V12 shuts off

Hi Ron,
A bit more info - all other projects open no problem, anything common to them is unlikely to be the problem. Once you have opened a project in a new version it cant be opened in a previous version. It was opening fine in V12 then just decided it wouldn't.

I dont have any plugins specifically for the problem project.

Many Thanks

Thanks Jim,

yes its too late.

this project was opening fine in V12 - until yesterday. It loaded in the morning but not later in the day.
All original files are backed up on a separate drive. My working computer is rarely connected to the internet.

Hello bomber127:

An idea. When Vegas gives the [I]Vegas has stopped working[/I] message, it generates a crash report. In that report it lists the offending items (paths, plug-ins, drivers, etc.). This may give you an idea about what is causing Vegas to fail.

Fortunately for me, it's been awhile since I've seen a crash report like this so I cannot remember just how to find it. Is it when you choose the option to report the crash to Vegas?

Good luck.

That's not the case on my system. You have to save the file from the new version (overwriting the previous) to lose the ability to open the file in a previous version -- not just open it. I do it all the time...

This is true for me as well. When I upgrade to a new version, I copy all of my projects in to a new main folder specifically for VP10, VP11, VP12, etc. In my case my projects are small and I don't save the media with the project so I can get away with this and not hog too much disk space.

I also have a "playground" folder and this is where I put my tests and maybe kinds of projects. Makes it easier for me to avoid corrupting my masters, which I have done a time or two when not paying close attention to what I was doing : (

Have you tried renaming the folder which contains your source files. Then when you open vegas will ask you to specify new location. Just a thought that it might load this way. Also, if the project stalls without actually crashing and you get the stopped responding white screen then sometimes it can recover if you wait a while. If you click and click you will get the prompt to wait for the program to respond or close.
I had a different issue and Vegas stopped responding but when I waited it came right in it own time.

Otherwise I fear you may be re-editing from scratch if you don't have a backup of the old project from whatever previous version you used.

Finally did you search your 'auto saved' whatever temporary location you specified in 'Options - Preferences - General' default is C:\Users\.....\AppData\Local\Sony\Vegas Pro\12.0\ to see if you have an auto save of the project before the problem.

thank you all,

the problem seems to be ntdll.dll issue. For some reason I can't copy the log to paste here.