How to Merge Two Partitions in Windows 11 or 10

You can combine two suitable partitions in Windows 11 by backing up the files on the partition you will remove, deleting that volume, and extending the partition immediately to its left. Disk Management does not automatically merge the two sets of files. Deleting the volume erases its contents; you must restore the files from your backup afterward.

The built-in route below covers adjacent ordinary partitions on a basic disk. It does not cover combining separate physical drives, moving recovery partitions, or rearranging a dynamic disk or Storage Spaces pool.

If your goal is a separate data volume spanning multiple physical drives, see our Windows 11 RAID and Storage Spaces guide. It explains mirrored storage and why that setup is different from merging partitions on one disk.

Decide Which Partition to Keep

A partition divides a disk into regions that Windows can use as separate volumes, such as C: and D:. “Merging” in this guide means removing one region and adding its capacity to another. It changes the disk layout rather than simply putting two folders together.

For the built-in method, the space you reclaim must become unallocated immediately to the right of the partition you keep, on the same physical disk. A drive letter does not tell you where a partition sits. Inspect the lower graphical view in Disk Management before deciding.

For example, a layout of C: → D: may allow you to keep C: and reclaim D: after a complete backup of D:. A layout of C: → Recovery → D: has a recovery partition between them. Do not delete that recovery partition to make these directions fit.

The partition you extend must use a supported file system. Microsoft lists NTFS or ReFS in its current volume-extension requirements. Do not format an existing partition just to enable an extension: formatting also destroys its data.

If They Are Two Physical Drives

Before deleting a volume, check its disk row in Disk Management. For example, C: and D: can be two partitions on Disk 0, or they can belong to Disk 0 and Disk 1. Those are different tasks. Deleting D: on Disk 1 will not create eligible space beside C: on Disk 0. The delete-and-extend method here is for suitable partitions on the same basic disk.

For two separate physical drives, decide whether you actually need a new pooled data volume. Microsoft’s Storage Spaces instructions require at least two additional eligible drives besides the Windows drive. A two-way mirror provides protection against one drive failure; a Simple space has no such protection. Neither layout replaces a separate backup.

Our linked RAID and Storage Spaces guide above gives the complete mirrored-data-volume procedure. Preparing a pool is a separate operation with its own backup, disk-selection and formatting checks. It does not enlarge C: using a second disk or automatically relocate existing files into one folder. If you simply want more room for documents, keeping the disks separate and moving selected data may meet that goal without pooling or deleting partitions.

Back Up and Check Dependencies First

Make a verified backup before deleting anything. Copy the files you need from both partitions to separate storage and open several important copies to check them. Our Windows 11 external-drive backup guide explains one approach and its coverage limits.

Check whether apps, game libraries, shortcuts, or backup jobs use the partition you plan to remove. Copying a program folder does not necessarily move an installed application correctly. Arrange any app-specific move or reinstall before removing its drive.

If encryption is enabled, confirm you can retrieve the appropriate recovery key. Microsoft explains where to find your BitLocker recovery key. Keep the computer on reliable power, close other work, and record the original layout.

Leave EFI, System, Recovery, boot, paging-file, and unfamiliar partitions alone. Microsoft documents restrictions on deleting system, boot, active paging-file, and crash-dump volumes in its volume-deletion reference. A disabled control is a reason to reassess the layout, not to force deletion with another tool.

Combine Adjacent Ordinary Partitions

Use an administrator account. The example below keeps a left-hand partition and removes an ordinary data partition directly to its right. The removed partition can have a different drive letter on your PC; identify it by its disk row, position, label, size, and contents.

1. Open Disk Management. Right-click Start and choose Disk Management. If you need elevated access, search for diskmgmt.msc, right-click the result, and choose Run as administrator. The lower pane shows each disk and its partition order.
2. Confirm the two partitions share the same disk row. Identify the one you will keep and the ordinary data volume immediately to its right. Check your verified backup and the applications that use that volume before continuing.
3. Delete only the identified right-hand data volume. Right-click it and choose Delete Volume. Read the warning and confirm only when you are prepared to erase that volume. Its former region should become a black-bar area labeled Unallocated.
4. Check the resulting layout before extending. The Unallocated block must now touch the right edge of the partition you are keeping. If it is separated by another partition or appears as free space inside an extended partition, stop and investigate the layout.
5. Extend the partition you kept. Right-click it, choose Extend Volume, and select Next. Choose the amount of eligible space to add; the default uses the available maximum. Review the selection, then choose Next and Finish.
6. Verify the result and restore your files. Check the increased capacity in Disk Management and File Explorer. Copy the backed-up files into suitable folders on the remaining volume, then check that they open. Keep the backup until the files and affected applications work correctly.

If your specific goal is enlarging the Windows system drive, our C-drive extension guide explains that narrower task and alternatives when suitable space is unavailable.

Why Is Extend Volume Unavailable?

Check adjacency, disk identity, permissions, and the file system. Space on Disk 1 cannot extend a basic partition on Disk 0 using this method. Unused capacity inside another existing volume is not the same as unallocated space.

Shrinking a partition releases space at its end. As Microsoft’s shrink-volume documentation explains, unmovable files can limit how far it shrinks. Shrinking D: in a C: → D: layout normally leaves the new space after D:, so D: still separates it from C:.

For an older extended-partition layout, or any layout you cannot confidently identify, seek help rather than deleting additional regions. Disk Management does not provide a general partition-movement feature. A specialist tool or planned migration may be appropriate, but its method must match your disk and backup.

Can You Keep Both Partitions’ Files Without a Backup?

This delete-and-extend method does not preserve the removed volume’s files in place. If you cannot verify a complete copy, leave the partitions separate. You can organize files across two volumes without merging them, and that may solve the practical problem with less disruption.

Can You Undo the Merge?

There is no simple undo that restores the deleted volume and its files. Shrinking the enlarged volume can create room for a new partition, but shrink limits may prevent the original size, and recreating a partition does not restore erased files. Recovery depends on the backup you made before deletion.

Before the destructive step, be able to answer three questions: which volume stays, which ordinary data volume goes, and where are the verified copies of its files? If any answer is uncertain, stop before changing the disk.

Use the Same Disk Management Procedure in Windows 10

On Windows 10, right-click Start > Disk Management, or press Windows + R, enter diskmgmt.msc and press Enter. Use the complete backup, disk-identity, adjacency, Delete Volume and Extend Volume procedure above. The same requirements apply: the ordinary volume you remove must be on the same basic disk and immediately to the right of the one you keep. Deletion erases that volume; Windows does not automatically preserve or combine its files. After extending, verify capacity and restore your backed-up files. An unavailable Extend Volume option does not justify deleting a recovery partition or formatting an existing volume.