But getting your old data back isn’t quite as simple as hitting “undo.” There are a few programs out there that allow you to “unformat” a partition or restore old partitions. But in most cases, I don’t recommend it. There’s just too great a chance that a “recovered” partition or “unformatted” disk would have something slightly amiss with it and would fail down the road. What I recommend is recovering the data from the corrupted or unbootable disk and then starting fresh.

This is actually not as hard as it sounds. A little tedious, maybe, but for the most part, you can recover some or all of your important files, even if your disk has been muddled beyond booting. Formatting or partitioning a file alters the boot sector, the file table, the partition table, and other parts of the disk that are typically separate from the data sector (where all your files are stored). So, it’s not like you’ve completed nuked your data - it’s more like you’ve locked your keys in your car. You’re going to need another way in.

 Data recovery software lets you mount a drive and do a raw scan of its contents. It bypasses the usual structure of file systems and partitions and reads through the data block by block. In doing so, it can recognize common files and sometimes even rebuild the filenames and file paths. Other times, it can only restore the content of the file. For example, you could find a completely intact photo, but the filename would be lost.

 For recovering data from a formatted, repartitioned or otherwise corrupted hard drive, I like to use R-Studio. R-Studio comes with a bootable version that you can run right off a burned CD. This is very handy, especially if you’ve gone and botched your system disk (rendering your computer unbootable). Booting in with the Live CD, you can run your file recovery operations and save the files you need to another external drive (NEVER save the recovered files to the same disk you are recovering from). From there, I do a complete full format of the corrupted disk and start fresh. I’ve had to do this many times on my own machines. Personally, I find that the best and safest way to dual boot or triple boot (e.g. Windows + Linux + Mac OS all on one hard drive) is to set up all my partitions BEFORE I start installing operating systems. Windows likes to attempt to usurp the master boot record, while OS X is very finicky about what type of volume it’s installed on, and just about every operating system gets format happy during initial installation.

 So, I hope I answered this reader’s question. My advice for recovering a formatted logical disk - whether it’s a Windows partition, Linux partition, or Mac partition - is the same for any platform. Use a third-party, bootable data recovery software, salvage your important data and then start over!