Fix External Hard Drive Not Initialized, I/O Device Error

To fix 'Disk Unknown Not Initialized' error on an external hard disk, you should initialize the disk at first. Some succeed, but some fail due to a successive error message 'the request could not be performed because of an I/O device error'. This page is to solve this type of [external hard disk not initialized I/O error]. Data recovery is a safe move to the troubleshooting part, and EaseUS hard drive recovery software can handle it well.

Table of Contents

Overview: external hard disk not initialized I/O error

What are the reasons that cause hard drive or external hard drive showing unknown not initialized on your PC? Here is a list of known factors:

  • Virus attack
  • Bad sectors
  • Partition Loss
  • File system corruption
  • Corrupted Master Boot Record (MBR)

Symptoms of the disk not initialized:

  1. 1. Disk shows as Unknown, Not Initialized with unallocated space.
  2. 2. Disk shows as Unknown, Not Initialized with no space displayed.

What's I/O error?

An I/O device error, short for Input/Output device error, happens when Windows is not able to perform an input/output action (such as reading or copying data) when it is trying to access a drive or disk. It can occur to many different types of hardware devices or media.

To fix 'Disk Unknown Not Initialized' error on an external hard disk, you should initialize the disk to GPT or MBR at first. Some succeed, but some fail due to a successive error message 'the request could not be performed because of an I/O device error'.

disk unknown not initialized i/o error

Combining the two consecutive error messages, here you are. When initializing a disk fails and you're caught up in the other unfamiliar I/O error, where is the way out? This page is to solve this type of [external hard disk not initialized I/O error].

Part 1. Recover data from external hard drive unknown not initialized I/O error

You should know that initializing a disk won't damage data, causing data loss problem at all. It's safe to initialize a disk to a normal state when it shows as unknown not initialized. 

To initialize a hard disk in Windows Disk Management:

Step 1. Connect the uninitialized external hard drive, HDD or other storage devices to your PC.

Step 2. Press Win + R keys to bring up Run, and type: diskmgmt.msc and hit Enter.

open disk management in Run box

Step 3. Find the uninitialized, unknown external hard drive with I/O device error > Right-click on it and select Initialize Disk.

Step 4. Then set the disk to initialize and set the disk as MBR or GPT.

initialize external hard drive to mbr or gpt to fix unknown not initialize error

However, this time is different. You cannot perform the manner of initializing a disk because of I/O error. So, you must turn to other workarounds instead of the most approachable one. Fixes beyond initialization could bring data loss, and it's smart for you to recover data from the inaccessible external hard drive before heading to the troubleshooting in Part 2.

EaseUS Data Recovery Wizard is renowned hard drive data recovery software, it's able to recover all types of files, like pictures, raw images and documents from a variety of storage devices, as long as the hard drive itself can be detected by Windows. If the hard drive is not showing up in Disk Management, try to make it visible.

To recover data from external hard drive with I/O error:

Step 1. Choose the external hard drive

Since you're going to recover data from the external hard drive, run EaseUS Data Recovery Wizard and choose the exact drive where you lost data. Click Scan.

select external hard drive

Step 2. Scan for lost data

The software will start immediately to scan all over the selected drive for all lost data. During the scan, you could see more and more data showing up in the results.

scan external hard drive

Step 3. Preview and recover data

After the scan is over, check the scan results for the desired data. You can preview the file by double-clicking on it. Click Recover and choose another location to save the recovered data.

preview and recover data

Part 2. Fix external hard drive not initialized with I/O device error

You're going to get rid of such pesky issue and fix external hard drive not initialized I/O error by going to [1] change a connection cable, [2] fix corrupted MBR, [3] use DiskPart command, and [4] remove virus from your PC/laptop.

The fix 2 and fix 4 are available on the linked pages, so we provide the detailed steps of how to use DiskPart command to clean the external hard drive. Since the CMD command would erase all data on the uninitialized hard drive, if you didn't recover data in advance, go to Part 1 to restore lost data after repairing the external hard drive not initialized error with DiskPart commands.

To clean the external hard drive with DiskPart:

Step 1. Press Win+R > Type: diskpart and hit Enter.

Step 2. Type: list disk and hit Enter.

Step 3. Type: select disk n and hit Enter; (replace n with the drive letter of an uninitialized external hard drive.)

Step 4. Type: clean and hit Enter.

Step 5. Type: convert gpt or convert mbr and hit Enter.

Step 6. Type: create partition primary and hit Enter.

Step 7. Type: format quick fs=ntfs and hit Enter.

Step 8. Type: assign and hit Enter.

Step 9. Type: exit and hit Enter.

Here, click to copy all the required command lines to fix an external hard drive not initialized I/O error, with the full error message 'the request could not be performed because of an i/o device error'.

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Updated by Gemma

Gemma is member of EaseUS team and has been committed to creating valuable content in fields about file recovery, partition management, and data backup etc for many years. She loves to help users solve various types of computer related issues.

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Written by Tracy King

Tracy joined in EaseUS in 2013 and has been working with EaseUS content team for over 7 years. Being enthusiastic in computing and technology, she writes tech how-to articles and share technical solutions about Windows & Mac data recovery, file/system backup and recovery, partition management and iOS/Android data recovery.

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