I accidentally reformatted a 1TB external hard drive from FAT32 to HFS+ Journaled (Mac OSX Extended Journaled). I've been looking at data recovery programs such as VirtualLab's Data Recovery and EaseUS Data Recovery. VirtualLab's Data Recovery runs and finds the correct size type/drive, but crashes with an exit code 217 when I try to build the files list. I have not run the EaseUS Data Recovery yet, but I'm planning on trying it after this.
However, I came across TestDisk, and have read that it may be able to recover accidentally formatted hard drives and preserve the filesystem (which I would like, since it is 1TB and my current hard drive doesn't have enough space to recover the entire disk to). However, I'm not entirely sure how to use TestDisk to do so. A deep scan is running at the moment, but I would like to know if it's at all possible to recover a FAT32 drive that has been accidentally formatted.