recover data on external HDD formatted by mac I connected an 1 TB Toshiba external HDD previously used on windows pc to my new MacBook Air and a message popped up for if I wanted to use this drive for time machine backup and since this is the first time i'm using mac I clicked "later". I think it got formatted so I tried some data recovery softwares but was unable to recover any data. I had lot of data on it which I would like to recover, is it possible?
To recover data from an external HDD formatted by Mac, you can use software TestDisk. Formatting is mainly performed when the HD gets corrupted due to software conflicts, bad sector etc. 
In Mac OS X, you can use ‘Disk Utility’ to perform the formatting process. Once formatting is completed, you can use advanced data recovery tool.