Many guys met this case that they want to change a new external HD and plugged into their computer. However, they couldn’t open it to access the files. They received this ERROR message: You need to format the disk before you can use it OR The disk in drive X is not formatted (appear in Windows XP). When not formatted error happens, here will occur a error message saying "disk in drive is not formatted, do you want to format it now".

Do you know to fix this problem? 

Here are several methods to fix the external hard drive not formatted:

Method 1: connect the external hard drive to another USB or another operating system, check if the files can be reading.
Method 2: restart the computer to try to read it.
Method 3: open anti-virus software to scan any virus on the external hard drive.
Method 4: Scan your hard drive and check the errors.
Open Start and typing CMD to open Command Prompt Window; 
Type “chkdsk g:/f” (if the external hard drive is Driver g:), click Enter;
Now, it will start repairing damaged files, it will ask if you want to save lost chains into another location. Click "Yes".

CHKDSK will take a long time to fix the error on the external hard drive, after the problem solved, the external hard drive will back to normal.

However, many computer users cannot scan the external hard drive using Command Prompt or they receive this message: the type of the file system is RAW, CHKDSK is not available for RAW drives. 

How to recover lost data from not formatted external hard drive?

Here MiniTool Power Data Recovery can help us to recover lost files from not formatted external hard drive. It is a powerful data recovery software, which has five recovery module: 
Undelete Recovery;
Lost Partition Recovery;
Digital Media Recovery;
CD/DVD Recovery;
Damaged Partition Recovery;

Step 1, Damaged Partition Recovery is specially designed for recovering data from damaged, RAW, or formatted partition. Click on Damaged Partition Recovery;
Step 2, Open the external hard drive and full scan it.
Step 3, after scan the external hard drive, it will show your lost files. Click Preview to check them;
Step 4, click Save to recover them to a right place.

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