I just upgraded from Flash Professional CS4 to CS5. Everything seemed to be working fine. After upgrading, I started working on a project I had been creating in CS4 on the new CS5. The file opened originally and I worked on it in the new CS5. My swf works and the video plays. All of the external swf files I load in to the Index swf work great. They were created in the new CS5. I can open the external swf, .fla files without any problem. But when I open the one Index file that was created in CS4, Flash CS5 crashes saying there was an unexpected error. I have uninstalled and installed flash several times. I have tried deleting the com.adobe.flash.plist file and restarting. Nothing has worked. I am really afraid I'm going to lose this file and all the work put in to it. Can anyone help me with some ideas to troubleshoot this? Any help would be greatly appreciated. Thanks.