2 Use Command Prompt. The Command Prompt tool in windows 10 is a reliable tool to fix some of the weirdest problems. The incorrect USB drive size issue in Windows 10 too can be fixed using this tool. I have a new 4.0 TB Black hard drive from Western Digital that I mounted in a Lacie external enclosure after removing a 2.0 TB drive. My new MacBook Pro's Disk Utility wants to initialize this disk but only recognizes the capacity as 1.8 TB. This is the second 4.0 TB disk with the same problem. Explains why a hard drive's capacity often appears to be less than advertised when displaying in Windows or Mac operating systems. Hard drive manufacturers market drives in terms of decimal (base 10) capacity. Plug in your USB drive to your computer, select the drive from the Destination Disk dropdown in the tool, and click on Parts Manage. A new screen will appear showing all the partitions available on your drive. You don’t need to do anything to them – just click on the Re-Partitioning button at the bottom. 'So, a kilobyte is actually 1,024 bytes, not 1,000, which is what it says on the box. Similarly, a megabyte is 1,024 kilobytes, a gigabyte is 1,024 megabytes, and so on.'

Hiya:

Gotta new iMac 27' running El Capitan and I'm in the process of transferring my files from my old Windows machine to my Mac. The drive in question is a 3TB Seagate drive that was NTFS formatted on my Windows machine. I never partitioned it and when formatted it displayed 2.32TB of available space in Windows 10.

I connected the drive via an external enclosure and USB (2.0) cable. OS X said it couldn't read the drive, so I transferred all of my files onto another external drive on my windows machine, connected it back up to my Mac, and formatted it to the Apple standard. It did format, however it says I only have 801.57 GB capacity, 801.44 available. I've ejected the drive, reformatted it, and chose the 'Apple Partition Map' as an option and still the same. I hope I covered all the bases?

Any help would be greatly appreciated, thanks!

- Jon K.

iMac with Retina 5K display, OS X El Capitan (10.11.2)

Posted on Dec 13, 2015 10:22 AM

My cloned hard drive shows wrong size, why?

When you upgrade to alarger hard disk drive (HDD) or solid-state drive (SSD) by cloning the old drive, youmay find the cloned hard drive has the same disk space as the original drive. In otherwords, the cloned drive not showing full capacity.

This is because when you clone a hard drive, you also cloned the partition size besides thedata. When the cloned drive is larger than the original drive, most of the cloning programs,if not all, will leave the extra space on the cloned hard drive as unallocated space. Andthen you will meet the issue that HDD/SSD shows wrong capacity.

In Windows File Explorer, you cannot see the unallocated space. That is why some users saythey have lost disk space after cloning hard drive. You can open Disk Management to see ifthere is unallocated space on your cloned hard drive.

How to fix cloned hard drive shows wrong size?

External Hard Drive Wrong Capacity Mac

There are two workaround solutions to fix the HDD/SSD shows wrong capacity. If you havefinished cloning the hard drive, you can go to Disk Management to handle unallocated spaceafter cloning. Or if you prefer a quick fix once for all, you can perform disk clone viaprofessional cloning software that can help you clone to a larger drive without causing diskcapacity loss.

Part 1. How to use full capacity of cloned hard drive

You can add the unallocated space on the cloned hard drive to the contiguous partition withDisk Management or DiskPart.exe. Follow the steps below to expand partitions after cloningin Windows 10/8/7 using Disk Management.

1. Press Windows + R key to open the Run window. Type“diskmgmt.msc” and press Enter to open Disk Management in Windows 10/8/7.

2. In Disk Management, right-click on the partition before the unallocated space, and selectExtend Volume.

3. Follow the Extend Volume Wizard to add unallocated space to this partition.

✍ Tips:
● If the partition and the unallocated space are not contiguous, you may encounter the issue“Extend Volume greyed out”.
● Besides extending volume, you can also use the unallocated space to create one or more newpartitions. Just right-click on the unallocated space and select New SimpleVolume.

If you can neither use the unallocated space to extend the adjacent partition nor create anew partition, then your cloned hard drive is larger than 2TB and it is MBR partition style.On MBR disk, disk space beyond 2TB will become unusable.

In this case, you can't use full HDD capacity after cloning unless you convert it to GPT disk. Converting a disk to GPTfrom MBR with Disk Management requires you to delete all the partitions on this hard drive.Then the time you spent on cloning hard drive is for nothing.

Or if you want a way to prevent cloned hard drive with unallocated space in the first place?Keep reading to learn more.

Part 2. How to avoid cloned hard drive shows wrong size

The key to cloning harddrives of different sizes without leaving unallocated space is to choose proper cloningsoftware. There is specialized hard disk cloning software called AOMEI Backupper Professional that canhelp you clone hard drive to a larger one without causing disk capacity loss.

External Hard Drive Showing Wrong Capacity Chart

• For cloning to a much larger HDD or SSD, AOMEI Backupper gives you three options tomanage the partition size. You can manually edit the partition size on the clone disk,let the program automatically adjust the partition size to fit up the entire hard drive,or clone without resizing partitions.

• When cloning MBR disk toGPT disk larger than 2TB, you will not lose disk space beyond 2TB because theprogram takes care of it. The cloned hard drive can still be used as GPT disk andremains bootable.

• When you upgrade to an SSD, it provides an option to align partitions to optimize forSSD. What’s more, it will not interrupt your work while cloning because of the volumeshadow copy service (VSS) technology.

Where Is My External Hard Drive

★ Step-by-step guide to clone to a larger SSD without unallocated space left

AOMEI Backupper provides an intuitive interface, which makes all operations in AOMEIBackupper quite easy. To upgrade to a larger SSD, you can follow the steps below.

1. Connect the target SSD to your computer and make sure it is detected. Install this programon your computer, and open it.

✎ Note: If there areimportant data on the target SSD, do backup files before cloning, or youwill lose them.

2. Select “Disk Clone” under 'Clone' tab.

3. Click on the current drive to select it as the source disk, and click on 'Next'.Then click on the larger SSD to set it as the destination disk, and click“Next”.

4. In the Operation Summary page, click on “Edit partitions” and then choosefrom the two options below to deal with unallocated space on the cloned drive:

External Hard Drive Showing Wrong Capacity Drive

- Add unused space to all partitions: the program will automatically extendall existing partitions with unallocated space.

- Manually adjust partition size: you can click on each partition and dragthe side bar to edit the partition size.

High Capacity External Hard Drives

5. Check the option “SSD Alignment”, which is important for keeping the SSDat its best performance. Then click “Start Clone” to execute the operation.

In this way, a cloned hard drive will not show wrong size no matter how larger yourdestination disk is. Also, you still can clone HDD to smaller SSDwith the same steps above. Besides the Clone feature, AOMEI Backupper has excellent backupand restore features, so users can use it to backup operating system, and restore to thenew SSD when their computer has only one SSD slot.

Conclusion

That’s all for how to fix the cloned hard drive shows wrong size problem. You can go to DiskManagement to add unallocated space. Or you can simply perform hard drive clone with AOMEIBackupper which allows you to manage the partition size to suit your new hard drive.