An inaccessible external hard disk is a serious problem, but it can often be solved without losing your data, as long as you take the right steps.
Errors like this can have a logical or a physical cause, and repeated repair attempts can make things worse. If the files matter, see how external hard drive recovery works, starting with a free diagnosis.
You’ve probably experienced the frustration of an error on your computer that you just can’t fix. Whether you’re working, studying or playing a video game, some problems can turn your time at the computer into a very stressful experience.
The “disk is not accessible” error is frequently reported by users of Windows 11, 10, 8 and 7, and in many cases it has a simple solution.
In this guide, you’ll learn what causes this error, how to solve it and how to recover data from a hard disk affected by it.
What does an inaccessible hard disk mean?
When your computer is unable to access or read a storage drive, you’ll see an error saying that the disk is not accessible.
This error means that the computer can’t access the data stored on the device, so the drive becomes inaccessible.
What to do when the hard disk is not accessible?
First, check that your user account has permission to access the drive. To do this, log in with an administrator account and try to open the disk.
Windows also has its own error-checking tool. However, if the disk contains important data that you don’t have a backup of, recover the data first: repairing the file system can remove damaged entries and make recovery harder. If the disk makes unusual noises, don’t run any tools at all.
- Open File Explorer;
- Select “This PC”;
- Right-click the hard disk icon;
- Go to “Properties”;
- In the Properties window, select the “Tools” tab;
- Click “Check”. The tool looks for and fixes file system errors, which solves some of the simpler problems.
If the problem persists, check the permissions:
- Open the Properties window again;
- Select the “Security” tab;
- Click your user name and then “Edit”;
- Tick all the boxes in the “Allow” column and make sure that none of the “Deny” boxes are ticked;
- Click “Apply” and then “OK”.
After these steps, try to open your hard disk again.
If these solutions don’t work, you can rule out a permissions problem. The next step is to find out what is affecting your drive.
What can cause problems with an external hard disk?
If your external disk is inaccessible, the cause may have nothing to do with user permissions. It could be a faulty connection cable or a problem with your computer’s USB ports.
Other factors can also affect your hard disk and leave it inaccessible or unrecognized, such as:
- Viruses;
- Other malware;
- Actions that corrupt data, such as unplugging the disk without ejecting it first, shutting down the computer incorrectly or using the device during power surges.
Can I just format an external disk that is denied access?
Formatting makes an inaccessible external disk usable again in many cases, but it should be the last resort, not the first, and only if the disk is physically healthy.
Before doing so, remember that formatting deletes all the files stored on the disk. Only format it if you don’t need the data or after you have recovered it.
If you want to recover data from your hard disk, don’t format it: read the next section, where we explain the options for data recovery.
If you have no data to save and want to format the disk, do the following:
- Right-click the disk drive;
- Select “Format”;
- Click “Restore device defaults” to use the default settings;
- Click “Start”.
When the process finishes, the disk will be empty and ready to use.
How do I recover data from an inaccessible hard disk?
If you have already checked the permissions, here are other solutions for the disk inaccessibility error that don’t involve formatting.
Solution 1: Be careful with “Initialize disk”
If Windows shows the disk as “Not initialized”, Disk Management will offer to initialize it. Don’t do this if you need the data: initializing writes a new partition table over the old one and makes recovery harder. First recover the data, and only then initialize the disk.
Data recovery programs such as Ontrack EasyRecovery can often scan an uninitialized disk and find lost partitions and files, whatever the brand of the disk (Seagate, SanDisk, WD or any other). Save the recovered files to a different disk. If the disk shows the wrong capacity or makes noises, the problem is physical and software won’t help.
- Once your data is safe, press the “Windows key” + “R” to open the Run window;
- Type “compmgmt.msc” and click “OK” to open Computer Management, then select “Disk Management”;
- Right-click the disk with the error and select “Initialize Disk”;
- In the dialog box, choose the partition style (MBR or GPT) and click “OK”.
Windows will then recognize the disk again, and you can create a new partition on it and format it.
Solution 2: Check or replace the cables
The cables that connect your hard disk to your computer may be causing the error. Check that they are properly plugged in and not damaged, try another cable and another USB port, and, if possible, test the disk on another computer.
Solution 3: Scan your computer for viruses and malware
As mentioned above, viruses and malware can be behind the malfunctioning of your hard disk.
Run a scan with your antivirus to make sure there are no malicious files preventing access to your drive.
Solution 4: Repair the file system with CHKDSK
If the file system on your disk is corrupted, Windows won’t be able to read the device properly. The CHKDSK command tries to repair the file system so that the files can be accessed again. As with the error-checking tool, if the data is important and you don’t have a backup, recover it before running CHKDSK, as the repair can delete damaged entries.
- Press the “Windows key” + “X” and choose “Terminal (Admin)” or “Command Prompt (Admin)”, then accept the request to run as administrator.
- Windows will open a command window where you can send commands directly to the operating system.
- Type
chkdsk E: /f, replacing “E” with the letter of the drive showing the error, and press Enter. The command may take some time, as Windows checks the integrity of the whole file system on that drive. - When the command has finished, type
exitand press Enter. - If Disk Management shows the disk as “Unknown, Not Initialized” or the space as “Unallocated”, see solution number 6.
Solution 5: Check the health of the external hard disk
If you’ve got this far and your external disk is still inaccessible, the problem may be bad sectors or physical damage.
A program such as CrystalDiskInfo shows the disk’s SMART data and tells you whether it is healthy. If it reports reallocated or pending sectors, don’t run surface tests (like the one in partition tools such as AOMEI Partition Assistant): they put extra strain on a damaged disk. Note that this check doesn’t recover any data; it only tells you whether the problem is in the hardware.
Solution 6: Recover the partition table (MBR)
Finally, the error may also be caused by a corrupted MBR (Master Boot Record), the area at the start of the disk that holds the partition table.
If your external disk is still inaccessible and appears as “Unknown, Not Initialized”, a partition tool such as AOMEI Partition Assistant can try to recover the lost partition and rebuild the MBR, making the data accessible again. Don’t create new partitions or format the disk in the meantime. If the disk shows the wrong capacity or none at all, the cause is probably a hardware fault, and it’s time to stop and call a specialist.
Is the data important? Recover data from an inaccessible hard disk with Bot
In this guide, we’ve seen how to deal with an inaccessible external disk and the errors it can show. If your drive has access problems, you now know the main steps to try safely.
If our tutorial wasn’t enough to get your data back, it’s best to turn to a specialist such as Bot, a company specializing in data recovery.
What’s more, collection of your device is free (islands not included) and the standard diagnosis is free too, which makes the whole process easier and more convenient for you.
Still have questions about an inaccessible external disk? Get in touch with Bot and leave your device in good hands, with professionals who can solve the problem and help you get your data back.
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