mac/pc issue with Pro Tools 7

[knorr]

I've just switched over to Pro Tools 7 as well as I have a brand new Intel Imac. Things seem to be working great but today I ran into an issue I haven't had before. When I opened up some of my old projects in Pro Tools 7 and wanted to save changes it made me create a new session file. I didn't think anything of this but if was a .ptf which was different from the .pts I saw in 6.9. So today I went to open one of those projects on a PC still running 6.9 and it wouldn't recognize the .ptf file and when I tried to open it, it said that Mac/PC compatibility was not enforced. However when I created this file a long time ago on 6.9 I am positive that I clicked this as I always have that on because I work back and forth on mac and pc.

So I went to my mac and created a new session and the "enforce Mac/PC" is not there. I don't see that button anywhere. Did they change this feature or what is happening here? Any ideas on why I can't open my Pro Tools 7 files in 6.9 on a PC when I had no trouble before going from mac to pc?

Thanks in advance.

[XSergeantD]

Ya do a Save Copy in and then change the Session Format section to 5.0-6.9?
PT 6.9 ain't gonna open a PT7 file unless ya do that.