X1 is (sometimes) Crashing when I load simple projects built in earlier versions of SONAR

see if there is any obvious differences in the projects for a start

e.g what plugins your using in each that differ.

Open the project in 8.5, mute all plugs and then close it. Open the same project in X1 and see if that works, I had a similar problem where the project in X1 would hang when loading, when I deactivated the plugs then it opened up. Strange...maybe a bug-maybe not. I hope it works for you though.

I've had the same problem from 8.0 to 8.5 to X1.  What I've done is save the plug-in preset as a file, in 8.0 or 8.5, whichever version is working, into the project folder.  Then either delete the plug-ins from the project and save, or remove all the plug-ins from X1, so none are scanned, disabling them didn't work.  X1 will open, telling you it can't find the plug-ins.  Delete the plug-ins from the project, save.  Rescan the plug-ins, place them back into tracks, or wherever, and load the preset.  What a hassle, but it works.
 
Tech support said it's my configuration.  Ok.  Maybe so.
 
I got lazy and didn't save a lot of presets in a lot of songs, so I have to re-install 8.0 or 8.5, with ALL the plug-ins, just to save the presets, so I can continue working in X1. 
 
I started with Cakewalk 1.0 on 5.25 floppies and have been a loyal customer ever since, so I wouldn't consider myself an amateur. 

Sorry - the post above should say:  "I deleted all soft synths from the project and X1 will now load the file."

Brandon / Seth - you all seeing anything like this?

  I had these problems from 8.5 to X1 Studio, and when deleting the old versions after upgrading to Producer. It's definetly the plug-ins crashing the program. 

To find out which plugin causes the problem, hold down the shift key, open file and then open project. All while holding the shift key. It will open one and one plugin, track by track, and when it crashes you'll know which one that causes the problem. If it's audio effects causing the trouble, reinstalling can be a solution. Fixed my problem. I'm still having problems with old projects and Dimension Pro though, could be because I installed the new version that came with X1P after uninstalling the previous.

Bub, on my machine it takes up to four minutes for Sonar to shut down after a crash and after quitting the process with the task manager. I used to reboot, but it took just as long just shutting it down then. So now I wait the minutes it takes and just restart the program.