External HDD is not accessible?

RAW means 'unformatted'. There's a good chance you can use it again if you format it again from Disk Management. This, of course, will delete everything that's on it. You do have a second copy (a backup or the original), don't you?

Kees

RAW means the information that Windows reads to tell what format the drive is in (and in turn your data) is not readable. This is characteristic of brand new drives that have not been formatted to any specific file structure: NTFS, FAT, HFS+, etc.

The partition table has been either erased or corrupted, and this can happen because of mechanical or logical reasons. If the data is important you will want to be careful how you proceed, and avoid DIY software as they can make the situation worse.

Try contacting a data recovery company like SERT Data Recovery (very reasonably priced) or KrollOntrack who is able to evaluate your drive to find out exactly what caused the issue. The first step is making sure the problem was not caused by mechanical failure, or bad sectors on the platter in which case doign anything other than bit level cloning after repair is sure to kill your drive and your data.

Was it on a windows computer, or instead on a MAC or Linux based computer and now you want to access it on a Windows computer? If that's the case, Windows doesn't care about file systems on hard drives other than FAT and NTFS types and will act exactly as you described.

It seems that the data on your external HDD lost. Sometimes it not realy loss, just can not access to it for the moment. Therefore, you still can get it back.
Have you ever tried any recovery tool?
If not, you can try 4Card Recovery.
Step one, download 4Card Recovery online and install it on your computer.
Step two, run it and choose the files that you want to recover, of course, you can choose recover all files in case of the omission of anything.
Step three, scan it by clicking the 'next' button and wait for about ten minutes.
Step four, save the recovered files on other part to avoid losing it again.
You can get all the lost files back after finishing the four steps, so easy.