Recover data from external hard drive that was Windows format and connected on a Macbook Pro. Did I lose everything? What happened?

Maybe this similar thread can help https://discussions.apple.com/thread/1508454

Don't worry, I met this situation before, I used a software called data recovery for Mac, it is realllllly helpful. you can google it or just download it from here: http://software.bigbigsoft.com/data-recovery-mac... wish you can find you data back~ 😉

If the Apple Store couldn't get files off of the drive, it is unlikely that you will be able to. If you have backups, those would be the best way to go. You could also try booting up the computer and holding down T to boot into Target Disk Mode. Plug the broken computer into another one with FireWire and see if it works to recover data from external hard drive. If you can see it, try booting up the broken computer while holding down Option. Choose Recovery HD from the menu, then choose to Reinstall OS X.

It is unlikely that this will work, because I'm pretty sure that the Apple Store would have tried this. You could try using expensive software to get files off the drive, but it would be risky and the results might not be any good.

https://discussions.apple.com/docs/DOC-4273

The external enclosure maybe faulty and are sometimes not the best places to test a drive.

Take the HDD out of the enclosure and plug directly into the main board. See if you can access it then.

It looks like your only route is professional data recovery like uFlysoft:

Step 1. Launch the software to scan the device where your files deleted

Step 2: Preview the scan result files and make mark if it is the one you find

Step 3: Recover files

http://www.uflysoft.com/data-recovery-mac/formatted-hard-drive-file-recovery.htm l