Last night I did a fresh install of Photoshop CS5 on my PC. After the install, I immediately chose "Updates" from the Help menu, and it installed all of the latest plug-ins, patches, etc. All pretty straightforward - the kind of thing we've all done a few times.
But this morning when I came to do some work, I found that there were a couple of CR2 files from one particular client which I couldn't view in Bridge, nor open in ACR (Adobe Camera Raw). I could see everybody else's raw files ok, it was just this one set.
I was totally perplexed, because I knew I'd viewed these files only a couple of days earlier, before the re-install. And what was more, I found I could open them just fine in Elements 9, so I knew the files themselves were ok. It was a problem with CS5.
But what was the problem? Like I said, I could open other raw files without any trouble. So I thought, well, maybe I didn't do the Updates properly? So I went to Help>Updates again, but it told me everything was up to date. I tried the same thing via Bridge - same result.
I'm happy to report I found the solution, and I'm posting it here on the remote chance that somebody else has this same problem, and finds my blog ...
I went to C:\Program Files\Common Files\Adobe\Plug-Ins\CS5\File Formats and found the file called Camera Raw.8bi. I deleted it, then went to the Adobe site and manually downloaded that file again. I put the newly-downloaded file into the folder, and launched Bridge - voila! I could see and edit all of my raw files again. Huzzah!
So I guess it means that the Camera Raw plugin file must have been faulty somehow. I don't know how it happened, but I'm very glad that my tale had a happy ending.
(I assume this problem and solution could apply to any version of Photoshop. If you're on a Mac, I believe the path to find your plug-in is /Library/Application Support/Adobe/Plug-Ins/CS5/File Formats.)