File not compatible- won't open in CS 5

Question

I have an image that I opened from Lightroom into PS CS5- it opened as a NEF (raw) file. I worked on it and saved it several times while working on it as a PSD. Now, when I go to open that PSD (from my external hard drive), it says that the file is not compatible with my version of PS. (It's the version I used to create the file.) Background: I tried updating Camera Raw last week, but it said that I first had to update PS Manager and something happened where that wouldn't update, so I gave up. I'm on a MAC version 10.6.6

Answer 1

By the way, Peter, I had meant to note. In the other thread you cited, you say:
>
Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000000
Crashed Thread:  0  Dispatch queue: com.apple.main-thread
>
This kind of crash at that location often means a bad font, or so I've been told.
This is actually an incredibly common failure, and it is much much more generic than bad fonts. It could be caused by bad fonts, but it could be caused by almost anything.
This indicaets a program has tried to defeference a pointer whose value is zero. That is, some function was passed a reference to some part of the program's memory (typically pointing to some data structure. It could be a number, a string, an TexttFrame, another function, a file, really anyting), and instead of that reference being an address, it was zero. And the function didn't check to see if thie address was valid, it just tried to read from address zero. Which, under many operating systems, including OSX, generates a trap and causes a crash.
So it's necessary to look at the stack trace to see what function generated the error. And that function was probably called be some other function by anothre function etc., and the fault is probably further upstream. If, e.g., the IDML export code calls the system's fprintf() function with a null pointer, the crash might be in fprintf(), but it would be the fault of the IDML export code.
Sometimes the faulting address might be more unique. Like if the pointer not zero but say, 3. There probably aren't too many cases where a pointer gets initialized to 3 by accident, so it might usually be the same thing. But address zero is incredibly common. (So are fun ones like 0xdeadbeef and 0xfafababe and 0xcafecafe).
Cheers. I wonder what happened with bizcomm...