Disk Unknown Not Initialized: How to Fix It & Recover Data

Disk unknown not initialized means Windows cannot read the disk’s partition table, often because the MBR is corrupted or the partition is lost. Check the disk in Disk Management: if its size is shown, follow Case 1; if not, follow Case 2.

What Does Disk Unknown Not Initialized Mean?

“When I plug in the drive, it says that it’s successfully installed however it does not appear in “my computer”. Also when I go into system tools it says that disk 1 is unknown, not initialized, unallocated. Can you please help me, I don’t want to lose my data, it contains all my pictures.”sevenforum

When a hard drive appears as “Unknown, Not Initialized” in Disk Management, Windows cannot read its partition information. This issue can affect internal and external HDDs or SSDs.

The disk may show unallocated space or no capacity at all. Common causes include a corrupted partition table, connection problems, damaged sectors, or hardware failure.

Before trying any fix, check whether the disk contains important files. Do not initialize, format, or create a new partition on a disk containing data you want to recover.

How to Fix Disk Unknown Not Initialized in Windows 11/10/8/7

Case 1: Disk Unknown, Not Initialized, Unallocated

Open Disk Management and find the uninitialized disk. If its capacity is displayed, Windows recognizes the disk, but the partition is lost or the MBR is corrupted. Try the solutions below in order.

Solution 1: Rebuild MBR

A corrupted MBR can trigger the “disk 1 unknown not initialized external hard drive” error. It may be damaged by malware, a power failure, or a mistaken operation. Rebuilding the MBR lets the system find the data again.

MiniTool Partition Wizard Free Edition can rebuild the MBR in a few clicks. Download and install it first.

MiniTool Partition Wizard FreeClick to Download100%Clean & Safe

Step 1: Run MiniTool Partition Wizard Free Edition.

Step 2: In the left pane of the main interface, select the unknown external hard drive and click “Rebuild MBR” from “Check Disk” menu. You can also right-click the target disk and select this function.

Step 3: You will be prompted back to the main interface. Here, click “Apply” to execute the change.

If the issue persists, try the next solution.

Solution 2: Recover the Lost Partition

If Disk Management shows unallocated space on the disk, try partition recovery. Do not create a new partition on it, or recovery becomes much harder.

MiniTool Partition Wizard’s Partition Recovery can restore the lost partition and its data. It is a paid feature available in the Pro Ultimate Edition.

Step 1: Right-click the disk with unallocated space and select Partition Recovery, or choose it from the Check Disk menu. If the disk appears as “bad disk”, you can still right-click it to start recovery.

Step 2: Select the scanning range for the specified disk. There are three scanning range as follows:

• Full Disk scans the entire disk, which is very useful for finding the lost partition.
• Unallocated Space helps to only scan free space.
• Specified Range scans specified sectors. When clicking this option, you can change “Starting LBA” and “Ending LBA” according to your needs.

Choose one of the scanning range as you like, then click “Next” to continue.

Step 3: Select a scanning method.

1. Quick Scanrestores your partition if your lost/deleted partitions are continuous. When the program finds a lost/deleted partition, it will jump to the end of the partition to continue scanning other lost/deleted partitions.
2. Full Scanwill scan each sector of the specified scanning range. If quick scan cannot find the lost partitions, try full scan.

Click “Next” to continue doing partition recovery.

Step 4: Wait for this scan to complete finding the lost or deleted partitions. After finishing a scan, all lost partitions will be displayed in the following list. Please select the partitions you need.

Here you can double-click the searched partition to explore its content. After selecting your desired partitions, click “Finish” to go back to the main interface.

Step 5: In the main interface, you can preview all lost partitions. Click “Apply” to execute all changes.

After recovery, the “disk 1 unknown not initialized external hard drive” error should be fixed, and your data should be accessible.

Solution 3: Recover Data from the Unknown Disk

If the disk holds important data and Partition Recovery cannot help, use the Data Recovery feature in MiniTool Partition Wizard Pro Ultimate. It can recover files from a not initialized hard drive in a few clicks.

Step 1: Choose the unknown not initialized disk and click the “Data Recovery” feature from “Check Disk“.

Step 2: This software will start scanning the selected disk; wait patiently until the scan completes.

Step 3: After the scan is complete, you can check the files that you need from the list it shows you. Then choose these items and click “Save” to recover them to a safe location.

Related article: Recover Data from Disk Shows as Unknown without Damaging It

For more information about case 1, you can watch the following video.

Solution 4: Initialize the Disk (Last Resort)

If the disk holds no important data, or you have already recovered your files, you can initialize it:

1. Press Win + R, type diskmgmt.msc, and click OK to open Disk Management.
2. Right-click the unknown disk and select Initialize Disk.
3. Choose MBR or GPT and click OK.

Case 2: Disk Unknown Not Initialized No size in Disk Management

If Disk Management is unable to show any information on neither this hard drive nor its disk capacity, the hard drive might have some disk problem or cartridge problem. Performing operations might be blocked by the “external hard disk not initialized I/O” error.

Solution 1: Check Cable, Port and Driver

A loose cable or faulty port often causes the I/O error. Try another cable and USB port, or connect the drive to another PC. If Device Manager shows a warning icon on the drive, update or reinstall its driver.

Solution 2: Turn off PC and Remove Battery

Perhaps disk unknown not initialized no size issue is caused by the PC motherboard issue. Just try to remove the battery to fix the issue:

1. Turn off the computer.
2. Disconnect the data and power cables from the problematic drive.
3. Remove the CMOS battery for ten more seconds.
4. Insert the CMOS battery.
5. Turn on the computer.
6. Shut down your computer.
7. Connect data and power cable of the problematic drive.
8. Start the computer.

If this method doesn’t work, please continue reading.

Solution 3: Replace the Bad External Hard Drive

Usually, Disk Management is unable to grab the disk information or the capacity of a disk that is unknown or not initialized. This issue could still exist even when you connect the disk to another computer.

In this case, you should take this disk out and send it to professionals for an inspection. If there is a physical error, the only solution to the unknown not initialized no size issue is to throw it away and replace this bad external hard drive.

In addition, there are still some disk problems in Disk Management, such as hard disk is not detected and hard drive space is missing, the following two articles could be useful.

• Hard Drive Space Is Missing? Take These Ways to Find It out
• 10 Cases: External Hard Drive Not Showing up & Best Fixes

Conclusion

In summary, this issue “disk unknown not initialized” can be solved quickly and easily with the assistance of MiniTool Partition Wizard. When addressing this problem, please try MiniTool products to rebuild MBR, recover partition and retrieve data. Hope you find this post useful.

Please leave a comment below or contact [email protected] if you have any suggestion or question. Thanks in advance!  

Disk Unknown Not Initialized FAQ