Why my external hard drive has less space than it should?

Why does my external hard drive have less space than it should? Because the space is not unallocated or the partition is damaged.

If your external hard drive shows less space than actual, one likely reason is that one of its partitions is corrupted. When a partition becomes corrupted, Windows may fail to recognize it properly and report it as "RAW" or simply leave it unallocated. In either case, the corrupted partition becomes inaccessible in File Explorer, and its storage space appears to be missing or reduced from the total capacity.

Corruption can occur due to improper ejection, sudden power loss, malware, or file system errors. Instead of displaying the corrupted partition normally, Windows Disk Management may show it as unformatted or with no drive letter, effectively making it invisible to everyday users. This can lead to confusion, as the space physically exists on the drive but isn’t being counted toward usable storage in File Explorer.

To recover the missing space, you'll need to inspect the drive in Disk Management. If the corrupted partition contains important data, you should first attempt to recover the files using data recovery tools. After recovery, or if the data is not needed, you can delete the corrupted partition and create a new one to restore full usable space on the drive. 

This is very effective solution to fix the external hard drive showing wrong capacity or not showing the full capacity in Windows file explorer.

It's understandable to be surprised when a new external hard drive has less space than it should. Here are some common reasons why this happens, along with explanations:

When you format a drive, some space is used for file system structures (like the file allocation table, root directory, etc.), which reduces the available space slightly. However, for a 1TB drive, this difference is usually only a few gigabytes. NTFS is efficient, but some space is always reserved for system files and metadata.
Some drives come with pre-installed software, backup tools, or hidden recovery partitions that occupy space. You mentioned no visible partitions, but it's worth double-checking: 
Use Disk Management (diskmgmt.msc) to see if there are any hidden or unrecognized partitions.
If there are recovery partitions, they may take up a small amount of space.
Rarely, if the drive has manufacturing defects, some space might be marked as bad sectors or reserved, but this is uncommon with new drives.
The most likely reason for the "less than expected" space is the difference between decimal (manufacturer's) and binary (Windows) measurements, which accounts for about 7-8% difference. For example, a 1TB drive (decimal) will typically show as around 930 GB in Windows.

What You Can do if external hard drive has less space than it should:
* Use a disk utility tool like Crysta1DiskInfo or Diskp0rt to see the total capacity and check for any hidden or reserved partitions.
* Open Disk Management and review all partitions on the drive.
* If the drive shows around 930 GB in disk management, it’s normal and nothing to worry about.

If your 1TB external hard drive has two partitions but only one shows up in File Explorer, the other partition might use an unsupported or unrecognized file system or unallocated space. This is why external hard drive has less space than it should. Below are two popular reasons.

Case 1: File System is RAW or Unrecognized

If it says RAW or has no recognizable file system:

The partition is likely corrupted or unformatted. To fix it (but this will erase all data):

Right-click the partition and choose Format.

Select NTFS or exFAT, name the volume, and click OK.

Case 2: Unallocated Space

If the second partition shows as Unallocated:

The partition has been deleted or never created. To restore it:

1. Right-click the unallocated space and select New Simple Volume.
2. Follow the wizard to assign a letter and format the volume.
3. It should then appear in File Explorer.

Still Not Showing? Try:

1. Reconnecting the drive using a different USB port or cable.
2. Checking it on another PC.
3. Scanning the disk with chkdsk or a third-party disk tool to check for hardware issues.

External hard drive has less space than it should? I’ve run into this kind of thing before. Basically, if your external hard drive doesn’t have enough space for what you’re trying to do—say, copying big files, installing updates, or even just saving stuff—it can cause some headaches. Windows might throw errors, freeze, or sometimes just not let you do what you want.

From my own experience, the main “danger” isn’t really about losing data or messing up your system, but more about it not working correctly. If the drive is nearly full, it might also slow down your computer or cause file corruption if you keep forcing things. So, it’s a good idea to clear some space or use a bigger drive if you’re planning to do anything big. 

When external hard drive has less space than it should. Just make sure there’s enough room before you do major transfers or installs. Otherwise, you might end up with a corrupted file or some weird errors. Nothing super risky if you’re just copying files, but it’s not great for performance or reliability.

If your external hard drive has less space than it should and you want a way to fix it, here’s what I’d suggest:

1. Delete Unnecessary Files: Go through your drive and remove stuff you don’t need anymore—old downloads, duplicate files, or backups you no longer need. Just be careful not to delete anything important!
2. Empty Recycle Bin: Sometimes, deleted files are still lurking in the Recycle Bin. Empty it to free up space.
3. Use Built-in Disk Cleanup Tool:
- Connect your external drive.
- Open “This PC” or “My Computer.”
- Right-click on your external drive and select Properties.
- Click Disk Cleanup.
- Check the boxes for files you can delete (like temporary files, system files, etc.) and hit OK.

4. Move Files to Another Storage:
If you have another external drive, cloud storage, or even your internal drive with free space, move some files there to free up space on the problematic drive.
5. Compress Files:
For files you don’t use often, consider compressing them into ZIP files to save space.
6. Use Free Disk Management Tools:
There are free programs like WinDirStat that show you what’s taking up space on your drive. It’s super handy to identify the big culprits.

If external hard drive has less space than it should on Windows computer and if after doing all this you still need more space, sometimes the best free solution is just getting a bigger external drive or splitting your data across multiple drives.