By Teresa / Last Updated May 25, 2020

Where is the missing space on my hard drive?

Last week, one of my friends told me that he has experienced a strange problem with missing space on hard drive. He purchased a laptop with 500GB HDD installed. In Windows Explorer, he found the C drive (280GB out of 300GB) is running out of space. He checked that all stored data don’t even get to 150GB. That is to say, he has nearly 130GB disk space missing? How come?

Actually, the strange situation is not strange to most users who are a little bit care about the hard drive capacity on the computer. Some users also find storage space missing on PS3 hard drive, XBOX 360 and portable hard drive. Windows missing space on hard drive account for different factors under different situations. For example, missing space after cloning and after partition are different. One may caused by unallocated space and the other may caused by incorrect cluster size.

When you purchase a hard drive, the seller won’t tell you that you actually buying a smaller disk. There is a different disk capacity algorithm between computer and hard disk manufacturers. Hard drive manufacturers take 1GB = 1000MB and 1MB = 1000KB out of convenience. Nevertheless, computer counts 1GB = 1024MB and 1MB = 1024KB. So the difference appears. Therefore, around 7% disk space missing on a hard drive is reasonable.

What occupies missing storage space on hard drive?

To find out the missing storage on the hard disk drive or SSD, we need to first figure out what caused the space missing, so that we can suit the remedy to the case. In general, we have following several events that take up the hard drive space without telling you.

  • Hidden partitions on the hard drive. Most laptops come with hidden partition like OEM partition and recovery partition. After upgrading to an advanced system, system reserved partition will be created automatically and set as hidden. You can see hidden partitions in Disk Management, or delete OEM partition if you have backed up system.

  • System protection on drive C. System protection is a feature that regularly creates and saves information about your computer’s system files and settings. It creates restore points just before significant system events, for example, install a program or device driver. If the restore points set to 50% of the drive capacity, much space will be taken. Check “System Volume Information” folder to view the data.

  • Hibernate file (hiberfil.sys) or Page file (pagefile.sys) that takes up the space. The kind of file is related to the random access memory (RAM) of your computer. Normally, it takes up several GBs. You can uncheck “Hide protected operating system files” to view it. You can also disable the system hibernation.

In fact, although you find what occupying the missing space, you cannot do much about these files. They are important to system running. Of course, above files are not the whole possible factors caused missing space on hard drive in Windows 10, 8, 7, XP and Vista.

Recover missing space from unallocated space

Except for aforementioned factors that may result in hard drive space missing, unallocated space is also a potential factor. For instance, after replacing a 500GB HDD to 1TB SSD, 500GB space is missing. All you got in Windows Explorer is the previous 500GB stuff. As a matter of fact, if you clone the 500GB HDD to 1TB SSD using sector by sector clone, the left 500GB space will become unallocated space on the hard drive and won’t show up in Windows Explorer. You can check this in Disk Management. Open it by typing “diskmgmt.msc” in Run box.

1. Right click the unallocated space and select “New Simple Volume” to create a new partition with that space. You can create multiple partitions using this space, just choose the size properly.

New Simple Volume

2. Alternatively, right click the partition before the unallocated space and select “Extend Volume” to extend partition to this space.

Extend Volume

In terms of making use of the unallocated space, AOMEI Partition Assistant Pro provides more options. Apart from creating and extending features, it allows you to move unallocated space to C drive, even if they are not adjacent. Many helpful features are embedded with this software as well.



After knowing what occupies the hard drive space, you definitely won’t complain missing space on hard drive, internal or external. We all know that the space is not really missing. Just find the way it act and take corresponding measures.