I have some projects that causes x2 to close but previously it doesnt. What might be causing it?

Possible project corruption - possible some plugin is messing things up.
 
You could try opening in Safe mode, and skipping any plugin loading, and see if that then allows the projects to open.  If that is the case, then you could go through the exercise of loading one plugin at a time until you find the one or ones it chokes on.
 
There may be other things to look at - those are the ones that come to mind for me, at the moment.
 
Bob Bone
 

Thanks Bob, what will i set to safe mode, the daw or the X2? If its the X2 where can i find its safe mode button? Thanks.

Safe mode is a special way of opening a Sonar project, and you can optionally load or skip the loading of each and every plugin.
 
Safe mode applies to a project, not to Sonar itself.
 
So, you would start Sonar normally, but instead of just opening the failing project as you normally would, instead hold the Shift Key and THEN open the failing project.  This will begin the Safe Mode processing.
 
When Safe Mode starts, Sonar will open a special dialog box (File Open - Safe Mode), where it will ask if you want to load each individual plugin present in the project, one at a time.
 
Here is where the process of trial and error begins.  It will ask if you want to load the first plugin.  Click Yes, and it will move on to ask if you want to open the next plugin.  Since you do not know yet if the 1st plugin will open properly, you want to skip the loading of all of the rest of the plugins, so that it will ONLY try to load the 1st plugin, so when it asks about the 2nd plugin, click No To All.
 
This tells Sonar that you do not want any of the rest of the plugins to open, and it will then try to open the project, loading only that 1st plugin.
 
If the project opens OK with just that 1st plugin, then you know that plugin is OK - close the project, open again in Safe Mode, tell it to load that 1st plugin, tell it to load the 2nd plugin, skip the rest, and see if opens with those 2 plugins.  If OK, then repeat the process until you get to where a particular plugin causes the project to fail to open.  Repeat the process, skipping that plugin, and move through the rest of them, skipping the ones that cause the project to fail.
 
At the end of it all, you will know all of the plugins that cause problems in the project, and you will hopefully be able to open the project, with at least some of the plugins, giving you a way to do something to get rid of the ones that are trouble.
 
You will have to swap the problematic ones out for other ones, or do something else, and it is all a pain in the rear, but that is the process.
 
Maybe someone has a better way of doing this - it is what I do when I have trouble - fortunately, this has only happened a couple of times, as I test all of my 32-bit plugins ahead of time, and now I only use 64-bit plugins.
 
While there are 64-bit plugins that do also cause trouble in Sonar, I don't have any that do it for me.
 
 
Good luck - let me know if the above makes sense, and if it works to at least get these projects open for you.
 
Bob Bone