I have, stupidly, upgraded to OS Lion on both my desktop and laptop. I've now done a hard restore on my laptop, back to Snow Leopard, and reinstalled my photo software, which wouldn't work with Lion. Now I need to remove Lion from my desktop, but must save 19,000 photos first, either by transferring onto my laptop (preferred) or onto my WD 2Tb hard drive, so I can reinstall after downgrade to Snow Leopard.
Crazy, I know, but I've never needed to do this before, so please be gentle with an upgrade novice.