Extend C drive

Extend C drive with Unallocated space in Windows 7

Windows Updates and many other types of files write into C drive every day, so sooner or later C drive will become full. In this situation, you can extend C drive without reinstalling Operating System and programs. A 256GB hard disk cannot be increased to 512GB itself, so before extending C drive you need to get some usable disk space. Unallocated is such kind of space. In Windows XP Disk Management, Unallocated space can only be used to create new partitions, but in Windows 7 Unallocated can be used to expand other drive with new Extend Volume functionality.

Extend C drive with Unallocated

However, Windows 7 Disk Management only works on few conditions. In this article, I’ll show you how to extend C drive with Unallocated space on Windows 7 (32 & 64 bit) using native Disk Management and third party partitioning software.

What is Unallocated space?

In a hard disk drive, the disk space that occupied by Operating System, File System and personal files are called Used space. Unused space of each partition is called Free space. As the name, Unallocated space is not allocated to any drive. But in fact, it only indicates that this area has no File System and is writable, but there may be files can be recovered. (When you format/delete a partition or delete files, only the records of the files are removed, but the real data is remaining. To Operating System, it is much faster and easier by this way, otherwise, it is a heavy work especially when there are large amount of files.)

How to get Unallocated space?

To get Unallocated space, you can accomplish in Windows 7 Disk Management without third party program. There are two ways to get by deleting or shrinking a drive.

  • Get by deleting: press Windows and R key on keyboard, types diskmgmt.msc and press Enter to open Disk Management. Right click the partition and select Delete Volume.
  • Get by shrinking: right click the partition in Disk Management and select Shrink Volume, enter the amount of space and click Shrink.

How to extend C drive with Unallocated?

Some people like to use Windows built-in utilities thinking that they are faster, safer or better because of some reasons. But when extending disk drive, native Disk Management is not the best choice, because Extend Volume works only when your disk partition configuration meets the requirements.

Requirement 1 – adjacent Unallocated space

From Microsoft, only the partition with adjacent Unallocated space on the right side can be extended with Extend Volume functionality.

It is impossible if you want to extend C drive by shrinking D. After shrinking D with Shrink Volume, Unallocated space is on the right side of D, so it is not adjacent to drive C, of course you cannot expand C drive with Extend Volume. This is the most common issue that Windows 7 users encountered.

Cannot extend volume

In the Disk Management of my Windows 7 testing computer, only drive D meets this requirement. I cannot extend C: drive, because the Unallocated space is nonadjacent. I cannot extend E: drive, because the Unallocated space is on the left side.

Requirement 2 – NTFS partition only

In fact, Extend Volume only supports NTFS partition, FAT32 and any other types of partitions cannot be extended even if there is adjacent Unallocated space on the right side. Luckily, this issue is only common for data drives, because most of system C: drive is formatted as NTFS.

FAT32 not support

Requirement 3 – same partition type

It is impossible to extend C drive by shrinking D, some people tried to delete D instead, so there will be adjacent Unallocated space on the right side of partition C, then Extend Volume is enabled. It is reasonable, but there is still restriction.

Unlike Windows 10 that formats the hard disk as GPT by default, Windows 7 formats disk as MBR style. There is a serious shortage with MBR disk that you can only create 4 Primary partitions, or 3 Primary partitions plus an Extended partition. Extended partition works like a container and all Logical partitions should be created in it.

You can extend a Primary partition by deleting the adjacent Primary partition, or extend a Logical partition by deleting the adjacent Logical partition. But you cannot extend a Primary partition by deleting a Logical partition, or extend a Logical partition by deleting a Primary partition.

Most of C: drive are Primary, so if you want to extend C drive by deleting D, drive D must be Primary, too. As you see in my computer, disk space of D is converted to Free instead of Unallocated after deleting, Extend Volume is disabled for C drive.

Extend c drive disabled

Extend C drive with Disk Management

As I said above, most of C: drive are formatted as NTFS and Primary, so to extend C drive in Windows 7 Disk Management, the only way is by deleting the adjacent drive D. In addition, drive D must be Primary partition. If your disk partition configuration meets these requirements, you can extend C drive by following the steps below easily.

  1. Back up or transfer all files in drive D to other partition.
  2. Open Disk Management and delete drive D.
  3. Right click C drive and select Extend Volume to combine the Unallocated space.

Note: if you installed programs in drive D, it is a BAD idea to extend C drive by deleting D. In this case, you’d better use professional partition software.

Extend C drive with partition software

Partitioning software is much easier and powerful. Here I’ll show you how to shrink D to expand C drive as example.

Step 1: Download NIUBI Partition Editor, right click the adjacent volume D and select Resize/Move Volume

Resize volume

Drag left border rightwards to shrink it in the pop-up window.

Shrink drive D

Click OK, Unallocated space is generated on the left side of drive D.

Drive D resized

Step 2: Right click C drive and click “Resize/Move Volume” again. In the pop-up window, drag the right border rightwards to combine the Unallocated space.

Extend C drive

C drive is extended to 50GB. (Remember to click Apply on top left to take effect.)

C drive resized

If you have shrank D and got Unallocated space, but Extend Volume is disabled for C drive, you just need to move Unallocated space to behind C drive.

Extend volume disabled

Right click drive D and select Resize/Move Volume, drag the middle position rightwards in the pop-up window.

Move partition D

Unallocated space is moved to the left side of drive D. Now you can right click C drive and combine this Unallocated space with “Resize/Move Volume” feature (same with Step 2)

Drive D resized

If you have deleted drive D but Extend Volume doesn’t work because D is Logical partition, you just need to right click C drive and combine the adjacent free space with NIUBI.

In Summary

Windows 7 provides Shrink and Extend Volume to change partition size, but few computer can meet the requirements. NIUBI Partition Editor can extend C drive with adjacent Unallocated or Free space on either side. If these space are nonadjacent, you can move them adjacent with NIUBI. Both NTFS and FAT32 partitions are supported, and there is no restriction between Primary and Logical partition.

Download to try

How to extend c drive with Unallocated space in Windows 7?
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