Looks like I'm gonna upgrade, quirks and pitfalls (if any) be damned....
Managed to corrupt my EM 1.x catalog somehow (Mac OSX 10.5 system), and discovered to my horror that I had NO BACKUP of the catalog. (Yes, Virginia, I HAVE read Peter's book, and regularly participate in his forum.) I lie prostrate before you all in my shame and grief.
None of the usual measures to un-bugger a catalog file have worked, so it's dead, Jim. It won't open in any version of EM, on any machine.
Fortunately, two mercies have been extended me:
1. I had installed EM2 beta recently and imported my existing images into it, but hadn't played with it much (ie, hadn't had the opportunity to foul it up);
2. I'm in the habit of embedding all my annotations into the original files, which are a mix of TIF's (scanned film mostly) and DNG's from various digicam original formats. I figured, that way I'd always have the data, and I could always strip out stuff I want no one to see when prepping files for export to others.
So luckily I was able to take my not-quite-up-to-date EM2-beta catalog file and fully update it, bringing in annotations with little or no loss. Rest assured, I will have backups going forward, with gratitude that the DAM Faeries occasionally cut a brother a break.
Now I gotta hope MS has done v. 2 right; or else wait for someone to offer a script to export Catalog Sets as Keywords, and make LR capable of DAM-ing 40k+ images!
Mike S. (The Chastened)