How to increase C drive space without losing data

by John, Updated on: February 18, 2021

This article introduces how to increase C drive space in Windows 10/8/7 (32/64 bit) without losing data. Increase C drive size by taking free space from D, E or with another disk.

Partition size is allocated by laptop/desktop OEM manufacturer or by yourself after installing Windows. Many types of files are writing into system C drive continuously, so it'll become full some day especially on SSD device. When it happens, you can add more free space to C drive without reinstalling Operating System and programs.

To increase C drive space for Windows 10 computer, there are two choices: Windows native Disk Management and third party partition software such as NIUBI Partition Editor. In this article, I'll introduce detailed steps to increase free space of C: drive in Windows 10/8/7 with both kinds of tools.

Increase C drive space in Windows 10/8/7 Disk Management

From Windows 7, there's Extend Volume function built in Disk Management tool, which is able to increase partition size without losing data (in most cases). However, your disk partition configuration must meed some requirements, otherwise, Extend Volume is grayed out. Windows 8 and 10 inherited the same function without improvement, so if you want to increase C drive in Windows 10 or in other version, check if your disk partition configuration meet the requirements below:

  1. The partition that you want to extend must be formatted with NTFS file system, FAT32 and other types of partitions are not supported.
  2. There must be adjacent Unallocated space on the right of system C: drive, if there's no such space, you must delete the contiguous partition on the right.
  3. If your system disk is initialized as MBR, the contiguous partition D (or E:)must be Primary partition.

Before running Extend Volume to increase C drive space, you must delete D to get contiguous Unallocated space. Do not delete it if you installed programs in it. If you can delete this partition, remember to transfer files to other place in advance.

How to increase C drive space in Windows 10/8/7 with Disk Management:

  1. Press Windows and R together on your keyboard, input diskmgmt.msc and press Enter.
  2. Right click D: drive and select "Delete Volume", then its disk space will be converted to Unallocated if D is Primary partition. (If it is a Logical drive, this method is invalid.)
  3. Right click C: drive and select "Extend Volume". (Extend Volume Wizard will be opened)
  4. Simply click Next till Finish to execute.

Extend volume wizard

Besides Extend Volume, there's another Shrink Volume function, why not extend C drive by shrinking other partition? This is because Shrink Volume can only make Unallocated space on the right, so this Unallocated space is non adjacent to C drive, of course Extend Volume doesn't work.

Extend Volume greyed out

Increase C drive space in Windows 10/8/7 with free partition editor

Better than Disk Management, NIUBI Partition Editor can make Unallocated space on either left or right while shrinking a partition. Therefore, you can increase C: drive size without deleting any partition. Other advantages of partition editor software:

NIUBI Partition Editor has free edition for Windows 10/8/7/Vista/XP home users. Better than other free and commercial software, it has Virtual Mode and Cancel-at-well technologies to avoid wrong operations, advanced file-moving algorithm to help resize and move partitions much faster. Professional and higher edition has unique 1-Second Rollback technology to protect system and data. If anything goes wrong while modify disk partition, it is able to automatically reverts computer to original status in a flash.

Download the free edition and you'll see all disk partitions with layout and other information. Available operations to a selected disk or partition are listed on the left and by right clicking. Unavailable operations are hidden to keep interface clean.

Main window

There are several ways to increase C drive space in Windows 10/8/7/Vista/XP, select the corresponding method according to your own disk partition configuration.

1. How to increase C drive space by shrinking volume D or E

In most of Windows laptop and desktop, there are other partitions on the same disk, then you can shrink any one to get Unallocated space and then add into C drive. Operating System, programs and associated setting, as well as anything else keep the same with before. No other operations are needed even if you use any types of hardware RAID arrays.

The partition that you want to shrink may be contiguous or nonadjacent to C drive, so there are 2 options.

Increase C drive space from D: drive (contiguous)

Better than Windows Disk Management, NIUBI Partition Editor can make Unallocated space on the left when shrinking D drive, no matter this contiguous partition is NTFS or FAT32, Primary or Logical partition. This is the easiest way.

How to increase C drive space in Windows 10/8/7/Vista/XP by shrinking D:

  1. Right click D: drive and select "Resize/Move Volume", drag left border towards right in the pop-up window, or enter an amount in the box of "Unallocated space before", then D is shrunk and Unallocated space is made on its left. Shrink D
  2. Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to combine this Unallocated space.
    Extend C drive
  3. Click Apply on top left to execute, then C drive is increased to 50GB by taking 20GB free space from D drive.Extend volume C

To avoid mistake, this software is designed to work in its virtual mode, the operations you do are listed as pending on bottom left. Real disk partitions won't be modified until clicking Apply to confirm and execute.

Increase C drive space from E: drive (nonadjacent)

If there is not enough free space in the adjacent partition D, you can get from other nonadjacent volume. It is similar but there's an additional step:

  1. Right click E: drive and follow Step 1 to make Unallocated space on the left side.
  2. Right click D: drive and select "Resize/Move Volume", drag the middle towards right in the pop-up window, then Unallocated space is moved next to C drive.
  3. Follow Step 2 above to merge Unallocated space to C drive.

How to increase C: drive space in Windows 10/8/7 with other partitions on the same disk:

Video guide

2. How to increase C drive size with another disk

In some Windows computers, the system disk is small especially if you use SSD, so there may be not enough free space on this disk. In that case, no software can add space to C drive from another separate disk. To solve this problem, you still have 2 options:

  1. Move a data volume to another disk, delete it and add its space to C drive.
  2. Copy whole disk to a larger one and increase C drive with extra disk space.

In Summary

This article introduces full solution to increase C drive space in Windows 10/8/7/Vista/XP, select the corresponding method according to your own disk partition configuration. Besides shrinking and extending partitions, NIUBI Partition Editor helps you do many other disk partition management operations such as merge, copy, convert, defrag, wipe, hide, scan bad sectors, etc.

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