cannot open core data model in Xcode

http://dl.dropbox.com/u/9开发者_运维百科580846/Screen%20shot%202011-08-21%20at%208.51.00%20PM.png

I get the following when when I am trying to view my .xcdatamodeld file. I started the project on Lion and I am sharing my projects with my macbook, which is running snow leopard. When I try to view the file I get the error shown above. The file is in the folder but I am not sure why I cannot view the file and edit my data model. Can someone please help?

Thanks

user831090 is right that the problem is the Tools Version. For the benefit of others (since I spent a long time googling for this) the exact error message is:

The file "elements" couldn't be opened because there is no such file.

To fix the issue, you need to change the Tools Version in XCode 4.1 on Lion. There is no option to change the Tools Version in earlier versions on XCode.

To do this, select the data model in your project tree, make sure you are showing the Utilities pane on the right hand side of the XCode window, and you will see a drop down to change the Tools Version. Change it to "XCode 3.2".