AOMEI Partition Assistant
How to Fix Pen Drive Showing Less Space Than Actual?
Pen drive showing less space than actual size? Here you can find a solution to let pen drive show full space.
By Irene / Updated on April 15, 2025
Why does my pen drive show less space than its actual capacity?
❓Hello, I'm experiencing a very strange problem with my USB drive. It's an ADATA UV350 64GB version. Today, I noticed in the formatting menu that the capacity is suddenly reduced to half. Is this a software bug or a wear issue? It's still under warranty, and I only use it a few times a month. Thanks for any advice and answers.
- Question from Reddit
While a lot of people said they had encountered the same problem, too. Generally speaking, a pen drive showing less space than its actual size happens in some specific situations. Here’s a simple table summarizing why a pen drive may show less space and how to fix it:
| Cause | Explanation | Solution |
|---|---|---|
| Sudden removal during use | Disconnecting while reading/writing can corrupt partitions. | Use Diskpart or a partition manager to clean and recreate partitions. |
| Interrupted or improper formatting | Using third-party tools incorrectly or stopping formatting suddenly midway. | Reformat the pen drive properly using Diskpart or partition software. |
| Installing bootable OS (e.g., Linux, Chrome OS) | Changes the drive's partition system, hiding some space. | Clean the drive and create a new partition using Diskpart or AOMEI Partition Assistant. |
| Virus or malware infection | Some malicious software can hide or use space. | Scan for viruses and then clean the drive using Diskpart or a partition tool. |
When users find that their pen drive showing less capacity than the actual, many may consider replacing it. However, don't be too quick to throw it away—there is still a solution. By fully cleaning the pen drive and creating a new primary partition, you may be able to restore its full capacity. The following article explains how to fix this issue step by step.
2 Solutions to pen drive showing less space than the actual
Now, you can try the following 2 solutions to check if the pen drive can show correct capacity then to fix it. To effectively fix the issue of pen drive showing less capacity, here is a fix methods comparison:
| Method | Tool | Steps Summary | Pros | Cons |
|---|---|---|---|---|
| Diskpart (Command Line) | Built-in Windows tool | Clean disk → Create primary partition → Format | No installation needed | Risky for beginners, easy to select the wrong disk |
| AOMEI Partition Assistant | Third-party software | Wipe disk → Repartition the pen drive | User-friendly, safer interface, effective | Requires installation |
!!! In order to avoid losing important data during fixing pen drive incorrect size issue, you can make a backup using backup software.
Solution 1. Use Diskpart to make pen drive show full space
The most simple way is to delete paritions on pen drive. Generally, you can use Windows Disk Management, but it does not allow you to delete volume on removable disk or delete/format system related partition. Thus, it comes to another Windows native tool named Diskpart.
Step 1. Connect the pen drive to your computer and make sure it is detected.
Step 2. Search “Command Prompt” in the Start menu. Right click its shortcut and select “Run as administrator”.
Step 3. Type “diskpart” → Enter.
Step 4. Type “list disk” → Enter. It will show you disks connected to the computer.
Step 5. Type “select disk #” → Enter. (Replace # with the number which is identified as the pen drive in your computer.)
Note: Be careful when entering the number, otherwise everything on the disk you choose will disappear.
Step 6. Type “clean” → Enter.
Step 7. Type “create partition primary” after you see “Diskpart succeeded in cleaning the disk”. If you want to create more than one partition on the pen drive, specify the partition size by this syntax: create partition primary size=#. For example, to create a 4000MB partition, run the command “create partition primary size=4000”.
When finish, leave the command window then you can format the pen drive easily through Disk Management as you wish. Of course, you can also format drive with Diskpart by executing command “format fs=”.
However, using Diskpart to fix a USB drive showing less space carries certain risks, especially for beginners. It's not always easy to identify which disk is your pen drive, and entering the wrong command can lead to data loss or system issues. For a safer and more user-friendly option, you can try a third-party partition manager instead.
🌟Solution 2. Fix flash drive showing less capacity with partition manager
AOMEI Partition Assistant is a safe and powerful disk partition management tool. It offers more features than Windows built-in tools like Disk Management, DiskPart, or File Explorer, and it supports Windows 7/8/10/11. Compared to DiskPart, AOMEI is much easier to use—even for users with little or no technical background.
To fix a pen drive, flash drive, or other USB device showing less capacity in Windows, you can completely wipe the disk and then repartition it. The detailed steps are as follows:
AOMEI Partition AssistantThe Best Windows Disk Partition Manager and PC Optimizer
Step 1. Install and launch AOMEI Partition Assistant, click the "Wipe" main tab and select "Wipe Hard Disk" option. (You can also right-click the Disk you want to wipe and select the "Wipe Hard Drive" option.)
Step 2. Select the disk you want to wipe and click "OK" to continue.
In this stage, you can also select a wiping method to wipe the selected hard drive according to your requirements and click "OK". (By default, the wiping method is Fill in 0.)
Notes:
- Fill in 0: Overwrite all sectors with zeros. It is common to wipe a personal hard drive. It is safe and fast.
- Fill in random information: It overwrites the hard drive with random data. It is more secure than the first one.
- DoD 5220.22-M: It will overwrite addressable locations on the hard disk with binary 0's, binary 1's, and a random bit pattern from once to seven times. The more times you choose to overwrite, the longer the process will take. Three times to five times are recommended. It is more secure than "zero-filling" and "random data filling" and faster than the Guttman. Thus it is often adopted by companies and organizations.
- Gutmann: It overwrites a hard drive with 35 passes. It is the safest way here, but it also takes the longest time.
Step 3. You can preview the shrink operation by viewing the "Pending Operations". To commit the "Pending Operations", please click "Apply" and "Proceed".
After wiping it completely, you can create a new partition on the unallocated space. Then the pen drive will show its full size.
Summary
Here are two solutions to “pen drive showing less space” problem in Windows PC. Now you can choose one relying on your situation. Apparently, AOMEI Partition Assistant provides an easier method. And you don’t need to worry about one mistake that causes data loss, because before applying, you can revoke at any time.
You can even get more advanced functions including recovering lost data, allocating free space from one partition to another, erasing SSD drive, converting boot disk from MBR to GPT for Windows 11 without deleting partitions, and more. For Windows Server users, AOMEI Partition Assistant Server is recommended.
