Fix MBR in external drive; it doesn't recognize the drive on laptop

Question

Fix MBR in external drive; it doesn't recognize the drive on laptop

Israel Baca 0

Deleted

This comment has been deleted due to a violation of our Code of Conduct. The comment was manually reported or identified through automated detection before action was taken. Please refer to our Code of Conduct for more information.

2 answers

Your answer

Deleted

This comment has been deleted due to a violation of our Code of Conduct. The comment was manually reported or identified through automated detection before action was taken. Please refer to our Code of Conduct for more information.

Answer 1

Hendrix-V 18,515 Microsoft External Staff Moderator

Hi Israel Baca,

Based on the symptoms you've described, the issue may not be limited to the MBR itself. When an external drive appears as unallocated, RAW, or cannot be assigned a drive letter, it can also indicate partition corruption, file system damage, or potential hardware problems.

As an alternative troubleshooting step, you can check whether the drive is being detected consistently by the system:

Open Device Manager and expand Disk drives.
Locate the external drive, right-click it, and select Properties.
On the Events tab, review whether Windows is reporting repeated disconnects, resets, or detection issues.
If available, test the drive with a different USB cable or USB port and confirm whether the drive shows the same capacity and model information each time it reconnects.

If the drive intermittently disappears, reports an incorrect size, or repeatedly reconnects, that may point to an underlying hardware issue rather than a repairable boot record problem.

If the data stored on the drive is important, it would be best to avoid formatting, initializing, or recreating partitions until you've determined whether the drive is stable and whether data recovery is needed.

I hope this helps provide another direction for troubleshooting. Let me know if you need further assistance, feel free to ask me by clicking "Add Comment" or "Add Answer" if you cannot add comment so your response will be visible. Thanks for your effort.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Israel Baca 0 Reputation points

2026-09-02T13:37:58.18+00:00

Hi; Last event on disk is when the drive turns on / off several times when I tried to read it in a tablet; This is the last info: 8/30/2026 9:13:37AM Device started (disk); There is no events after that.
Israel Baca 0 Reputation points

2026-09-02T13:44:10.6+00:00

Disk is shown as Unknown and not initialized with no partitions; In Device Status is showing as working properly.
Hendrix-V 18,515 Reputation points Microsoft External Staff Moderator

2026-09-03T01:55:42.0033333+00:00
Hi Israel Baca,

Thank you for providing those additional details. Since the drive appears in Device Manager as working properly, but Disk Management shows it as Unknown and Not Initialized with no visible partitions, Windows is still detecting the hardware itself. That suggests the USB connection and drive controller are at least responding to the system.

Given that the last recorded event was simply the device starting and there are no subsequent error events, you could try checking whether the disk is returning valid information directly to Windows:

Open Command Prompt as Administrator, run:

diskpart list disk

Check whether the external drive reports a normal size (for example, 500 GB, 1 TB, etc.).

If the drive shows the correct capacity, that can indicate the hardware is still communicating and the issue may be limited to the partitioning or disk metadata. If the size appears as 0 bytes, is unavailable, or changes between reconnects, that may point to a lower-level hardware problem.

Since the drive was repeatedly powering on and off when connected to the tablet, it may also be worth testing it on another computer and observing whether it remains connected continuously or disconnects unexpectedly.

As the disk is currently showing as Not Initialized, I would avoid initializing it for now if there is important data on the drive, as doing so could complicate recovery efforts later.
Israel Baca 0 Reputation points

2026-09-03T13:45:39.7533333+00:00

Hi; Disk is online but Size is 0B
Hendrix-V 18,515 Reputation points Microsoft External Staff Moderator

2026-09-04T02:06:02.3933333+00:00
Hi Israel Baca,

Thank you for checking that. The 0 B size result is an important detail.

If DiskPart shows the disk as Online but reports a capacity of 0 B, Windows can see that a storage device is connected, but it is not receiving valid capacity information from the drive. In that situation, the issue is typically beyond a missing partition or damaged MBR alone.

At this point, you could test the drive:

With a different USB cable (if removable).

On another PC.

Without any USB hub, adapter, or tablet dock in the path.

If the drive continues to report 0 B capacity across multiple systems, there may be a communication problem between the enclosure and the disk itself, or the disk may no longer be able to provide its geometry information to the operating system. In that case, software-based MBR repair tools are unlikely to detect enough disk information to perform repairs.
Israel Baca 0 Reputation points

2026-09-10T13:20:48.7933333+00:00

Hi; I have tried with a different USB cable, I changed the enclosure, different PC and drive continues Online and 0B. Disk is spinning normally; just once it seems to be doing some clicking noise. Thanks

Answer 2

If the external drive is no longer recognized after MBR changes, the practical recovery path is to check whether Windows still sees the disk, then recreate the partition if the disk shows as unallocated.

Check whether the disk is detected
- Right-click Start > Disk Management.
- If the drive appears there as Unallocated Space, the disk is present but has no usable partition.
Create a new partition in Disk Management
- In the bottom pane, right-click the Unallocated Space on the external drive.
- Select New Simple Volume and accept the defaults.
- This should make the drive appear again in File Explorer.
If hidden or old partitions are blocking reuse, wipe and rebuild the disk with DiskPart
- Warning: this erases everything on the external drive, including hidden recovery or system partitions.
- Open Command Prompt as administrator.
- Run these commands in order:

DiskPart
list disk
select disk <external disk number>
clean
create partition primary
format fs=ntfs quick
exit

clean removes all partitions and formatting from the selected disk.
create partition primary creates one full-size partition.
format fs=ntfs quick formats it for normal Windows use.

If the drive still is not detected correctly
- Open Device Manager and check for USB or disk devices with an exclamation mark.
- If a device shows a problem, uninstall that device and then select Action > Scan for hardware changes.
- Try the drive on another PC. If it also fails there, the issue is likely with the drive itself rather than the laptop.
If the goal is specifically to verify MBR/GPT state
- Open an elevated command prompt.
- Run:

DiskPart
list disk

In the Gpt column, an asterisk means GPT. A blank value means MBR.

If the disk is visible in Disk Management but not in File Explorer, recreating the volume is usually enough. If the disk is not visible on multiple PCs, focus on hardware failure rather than MBR repair.