My Passport Lights but not detected by computer

I had purchased external portable storage device. When connected, it lights up and advises me that the device be formatted for use. How to format without losing data. If there is a chance of losing data, then how I retrieve data? Please advise.

Hi,

A steady power led light on the WD My Passport drive signify that the hard drive is getting power but it is in idle state. It would blink fast while data transfer.

‘Format the drive’ message is most probable to occur if your external hard disk has been corrupted. You could use third party data recovery tools mentioned in the link provided below to recover the data from it.