HOWTO: get those files back from FileVault

Question

Hi,
An update of OS X on my MacBook became unstable, and I was no longer able to get to a login screen. Panic rising ....
My files (read: my research from the past two months) were locked with FileVault. (I now would recommend against keeping FileVault on most of the time.) So when I put the MacBook in target disk mode using another Mac, I saw absolutely nothing in my home directory. Panic rising ....
I call up AppleCare, and they were very helpful and polite, but after a few hours they did not see a way around the problem. Panic maximum! Begin doomsday plan-making for life after loss of precious data.
Eventually, after about 24 hours of fretting and wishing I could have those two months of my life back, I tried the following absurdly simple instructions. For this, you need is your troubled Mac, an untroubled Mac, and a FireWire cable. (If you don't have these items, my experience is that the people at the Mac store will probably let you use theirs for at least a little while ...)
1. Startup your troubled Mac in single-user mode. (Hold command-s immediately after pressing the power on, till you see a black screen with tons of text.) This will take you into a text-y environment.
(If you are afraid of text-y environments, don't worry: things are set up so you can't do much harm unless you're really trying.)
2. Type "mount -uw /" at the prompt (without the quotation marks, of course).
3. If nothing particularly dramatic happens (e.g., it thinks for a bit and then gives you another prompt, that means there's still hope.
4. Type "cd /Users".
5. Type "ls".
6. You should see all the users, and maybe a few directories called ".username" or the like.
7. Look in your home directory for a file called "yourusername.sparseimage" ("cd yourusername"; "ls").
8. If it ain't there (and I guess it probably won't be), look in the directory called ".yourusername" ("cd ../.yourusername"; "ls"). If it's there, you are in pretty good shape.
9. If not, keep looking though all those directories till you find it. If you can't find it this way, that's probably a bad sign. Let me assume instead that you did find it, in a directory called "somewhere".
(Let me point out that if you like text-y environments, you might be inclined to try to mount the spareimage in single-user mode by piping your password in. This doesn't seem to work, and I don't really know why not.)
10. Now type "reboot". When the machine reboots, press and hold the t key till you see the floating symbol. This enters you into target disk mode. Use your FireWire cable to hook your machine up to your working Mac.
10. On your untroubled Mac, the volume for your troubled machine will be named something like "Macintosh HD 1", to distinguish it from the hard disk of the non-defunct computer. Whatever the name is, remember it! Let's call it "DefunctVolumeName".
11. Open the volume in Finder.
12. Now look to see if your directory "somewhere" shows up in Finder under "Users". If it does, great! It probably won't, though, and that's OK!
13. If you're like me, you found "yourusername.sparseimage" in a directory called ".yourusername", which Finder doesn't show you. That's because it's a secret. Whatever the name of the folder was, click on "Go" and then on "Go to Folder..."
14. In the window, type "/Volumes/DefunctVolumeName/Users/somewhere", using the information you learned from the above experiments.
15. Out of nowhere, your hidden folder appears, hopefully containing the sparseimage file you found when you were tooling around in Single-user mode.
16. Open that sparseimage file. The machine will ask you for a password, and you should type it. The machine will warn you of instability as a result of mounting that sparseimage file, but, hey, do you want your files or not?
17. Get those files off!
18. Say thanks to your favorite deity.
When you write it out this way, it doesn't look like a particularly clever trick, but this one stupefied me, the techies at the Mac Store, and the folks on AppleCare.
I hope this helps someone!!!

Answer 1

If you also backed up to your computer - you can restore from that backup - to retrieve the files. As far as I know- that should have no bearing on deleting them from iCloud - they should still be in that backup.
If you used iOS file sharing with your computer - and saved the files to your computer - you can retrieve them from there.
if the only place that the files were saved to was iCloud, I know of no way to get them back.