How to Merge Two Partitions in Windows 11

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.

This works the same way in Windows 11 and Windows 10. The partition you remove must sit immediately to the right of the one you keep, on the same physical disk. It doesn’t apply to separate drives, recovery partitions, dynamic disks, or Storage Spaces pools.

Before You Start

Warning: deleting a volume erases everything on it. Copy the files you need to an external drive (see our Windows 11 backup guide) and open a few copies to check them. Move or reinstall any apps or game libraries on that partition. If BitLocker is on, have your recovery key ready. Never delete EFI, System, Recovery, or unlabeled partitions (Microsoft lists volumes Windows won’t delete). The partition you extend must use NTFS or ReFS, per Microsoft’s extend-volume requirements.

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.

If the Partitions Are on Two Physical Drives

Check the disk rows in Disk Management. Space on Disk 1 can’t extend a partition on Disk 0. To combine separate drives into one data volume, use Storage Spaces, which needs at least two extra drives besides the Windows drive. Our Windows 11 RAID and Storage Spaces guide walks through it. Pooling doesn’t enlarge C: or move your files, so keeping the drives separate is often simpler.

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 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.