External hard drive not showing up in Windows 10
With large capacity, External hard drive, also called portable hard drive, is always used to store or back up data. In most case, external hard drive or second hard drive will present automatically after connected to your computer. However, it is possible that the external hard drive not showing up in Windows 10 File Explorer or “This PC”. Then, you won’t be able to open it to use the files stored on it.
Solve external hard drive missing in Windows 10 step-by-step
When you encounter a similar issue, you can follow the guide listed below to fix it effectively. First of all, let’s open Disk Management to see the condition of this hard drive. And you can take acorroding solutions if it is showing up in Windows 10 Disk Management or not appearing in Disk Management.
▶ Condition 1. Extern hard drive not appearing in File Explorer but showing in Disk Management
▪ Solution 1. Assign a drive letterh
▪ Solution 2. Initialize external hard drive
▪ Solution 3. Rebuild MBR without data loss
▶ Condition 2. External hard drive not showing up in Disk Management
▪ Solution 1.Check Windows driver via Device Manager
▪ Solution 2. Examine USB port and enable USB Device in BIOS
▪ Solution 3. Diagnose the external hard drive
→ External hard drive not showing up in File Explorer but in Disk Management
Press “Windows”+ “R”, type “diskmgmt.msc” and hit “Enter”, you will access Disk
Management interface. When the hard drive is not showing up in File Explorer but
appears in Disk Management, you can try the following methods.
Solution 1. Assign a drive letter to the external hard drive
When the external has no drive letter, it will be invisible in File Explorer. At this
time, you should assign a drive letter. Firstly, right click the partition that
doesn’t have a drive letter and choose “Change Drive Letter and Path...” Then click
on “Add”, choose a drive letter and click “OK” to give it a drive letter. After
that, you can access the hard drive from File Explorer.
Solution 2. Initialize external hard drive
When the external hard drive is not initialized and appears as an unallocated space
or without showing disk capacity, you can initialize it as follows:
1. Right click the hard drive that needs to be initialized
2. Select “Initialize Disk” and set the disk partition style as MBR or GPT.
3. Right click the disk and choose “Create New Simple Volume”.
Notice: As initialization will cause data loss, you’d better
backup all the important data on the external hard drive before initializing it.
Solution 3. Rebuild MBR without data loss
It is well-known that MBR or Master Boot Record is essential to a hard drive. When it
is damaged by some accidents such as virus attacks or inappropriate operation, the
hard drive might display as unknown and not initialized external hard drive in Disk
Management. Under this case, what you should do is to rebuild MBR via reliable and
software - AOMEI Partition Assistant Standard.
First of all, free download AOMEI Partition Assistant Standard.
Install and fire up it. Then you can follow the steps to rebuild MBR on the external
hard drive.
Step 1. Right click the uninitialized disk and choose “Rebuild
MBR”.

Step 2. Set the type of MBR based on your current
operating system. Then, click “OK”.

Step 3. Click on “Apply” to implement this operation.

Note: You can get more advanced functions, like recoverig lost partition on external hard drive, converting system disk from MBR to GPT without data loss, if you upgrade it to Professional version.
→ Hard drive not showing up in Disk Management
If the external hard drive is not recognized by Windows 10 and doesn’t display in
Disk Management, it is likely that there is something wrong with USB port, Windows
driver and so on. To solve the problem external hard drive not showing up in Disk
Management on Windows 10, you have to take specific steps based on different
situations.
Solution 1. Check Windows driver via Device Manager
When Windows 10 Disk Management doesn’t list the external drive, you can check
whether there is a driver problem on Windows via Device Manager.
1. Press “Windows”+ “R”, enter “devmgmt.msc” and hit “Enter”.
2. Click “Disk Drives”; if the external hard drive is with a yellow exclamation mark,
it is problematic.
3. Right-click the problematic drive, select “Properties”, and read the message
carefully.
4. To fix such error, under Driver table, click on “Update driver” to install updated
drivers. Or you can click on “Uninstall” to uninstall the driver and restart your
computer; after rebooting, the driver will be automatically reinstalled and
reconfigured.
Solution 2. Examine USB port and enable USB Device in BIOS
If you can’t find out the external hard drive even in BIOS, it might be caused by
disabling interface in BIOS. Thus, you can enter BIOS to enable the USB device. Then
restart your computer to see whether the problem is solved. If you still can’t see
the drive in BIOS, you can check the USB port is “OK”.
First of all, you need to
unplug the external hard drive and plug it into another USB port to see if it works.
If you have connected the drive via USB hub, connect it to computer itself. Then, if
you can see the drive in Disk Management but not in This PC, you take measures
narrative in previous part.
3. Diagnose the external hard drive
Having done all of these, if the problem external hard drive not showing up in Disk
Management Windows 10 still exists, don’t hurry to abandon the external hard drive
might be dead. You can employ professional hard drive diagnostic software to check
if you have to replace this external hard drive.
What if external hard drive appears but not recogznied in File Explorer?
If the external hard drive's file system is corrupted or incompatible with Windows 10 , it won't be accessible even it shows up in File Explorer. If you open it, you can receive an error, like "X drive is not accessable access is denied". In such case, you can format external hard drive to certain file system compatible with Windows system.
The tool mentioned above, AOMEI Partition Assistant Standard will be a nice solution. It allows you to format external hard drive like Samsung and WD external hard drive etc. to FAT32 without the limitation of 32GB in partition size, exFAT or NTFS effortlessly. The detailed steps are as follows:
Step 1. Run AOMEI Partition Assistant Standard. Right click the external hard drive partition that you need to format and choose “Format Partition”.

Step 2. Choose one file system compatible with Windows system and click “OK”.

Step 3. Review the operation and click “Apply” to implement it.

Warning: Formatting external hard drive partition will delete all data on it. If there is any important data, you’d better backup or transfer it to somewhere before formatting.