The term raw disk refers to the accessing of the data on a hard drive disk (HDD) or other disk storage device or media directly at the individual byte level instead of through its file system as is usually done. That means users cannot access the files on the raw disk. Generally, many accidents will cause your disk or partition to become raw, say, virus attack, wrong format, power failure or surge, system crash, etc.
A friend of mine once went to format his drive to NTFS, while the drive showed as “File System: Raw” after he formatted the drive. He had no idea how the disk failed and just attempted to recover some of the important files from the raw disk.
Yes, if a disk reads as raw in Windows, possible (but not all) symptoms are:
Invalid media type reading drive.
Abort, Retry, Fail?
File system is displayed as "RAW".
Windows may ask if you want to format the drive, such as warning "disk not formatted. Do you want to format now?"

File names contain "weird" characters.
"Sector not found" messages.
For this situation, data recovery for raw disk or partition is possible for you. But the most important tip you must hold firstly: Do not make any change to the raw disk before the data on it is recovered! If not, your data will be a larger exposure to data loss risk.
No doubt, not all lost data recovery has to go to data recovery service, instead, to recover data from raw hard disk or partition, data recovery software is highly recommended for your DIY data recovery. EASEUS Data Recovery Wizard, especially designed for data recovery from raw hard disk or partition, accidently deletion, format, virus attack, system crash, etc. for Windows, will efficiently recover your data from raw disk or partition.
Here you can download a free demo to try! The demo version gives you a much fairer idea about chances of data recovery from your hard disk before deciding upon the purchase.
As for the step-by-step instructions of recovering data from raw disk or partition, please refer to the details how to recover raw disk(s) or partition?
Related articles:
Easy and Safe Solution for RAW Partition RecoveryBest Solution for RAW Files Recovery
How to Recover and Rescue Data When "Disk not Formatted…" Pops up?
