Can't Extend C Drive with Unallocated Space in Windows 10/11

Q: Why can't I extend my C drive even though there is unallocated space?

Windows can only extend C drive if the unallocated space is immediately to its right. Partitions or recovery partitions between C and the free space will block the extension.

Q: Can I extend C drive safely without losing data?

Yes. Using IM-Magic Partition Resizer Free, you can safely move partitions and extend C drive without losing files.

Summary: If you are unable to extend C drive with unallocated space in Windows 10 or 11, this guide explains why and shows how to fix it safely using IM-Magic Partition Resizer. Learn solutions for when you are not able to extend C drive.

Why You Might Be Unable to Extend C Drive

Unallocated space is not adjacent: Windows requires unallocated space to be immediately to the right of C.
Unallocated space is not at the right: Windows requires unallocated space to be at the right side of the C drive.
Recovery/EFI or system partitions block C: OEM, recovery, and EFI partitions may sit between C and free space.
C drive is FAT32 or disk uses MBR: Only NTFS partitions can be extended; MBR disks have partition limits.
Disk errors or corruption: Bad sectors may prevent safe resizing.

How to Fix “Can't Extend C Drive” Using IM-Magic Partition Resizer

Video: How to fix not able to extend C drive

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Step 1 — Download and Install

Download IM-Magic Partition Resizer Free from the official site resize-c.com, install it, and launch the program.

Step 2 — Check Partition Layout

Identify your C drive and the unallocated space. If any partition lies between C and the unallocated space, it must be moved first.

Step 3 — Move Partitions

Right-click the partition (the one that has contiguous unallocated space) between C and unallocated space.
Select Resize/Move.
Drag it to the right so unallocated space becomes adjacent to C.
Repeat if multiple partitions exist.

Note: You can only move a partition if unallocated space is immediately adjacent to it.

Step 4 — Extend C Drive

Right-click C drive and select Resize/Move.
Drag the boundary to include the unallocated space.
Click OK and then Apply Changes.

Step 5 — Verify

Open File Explorer or Disk Management to confirm C drive has increased in size. All data should remain intact.

Also read: How to move unallocated space

Additional Tips

Back up important files before resizing.
Run chkdsk C: /f /r if resizing fails.
Convert FAT32 → NTFS if C is not NTFS.
Convert MBR → GPT if partition limits prevent extension.

FAQ

Why can't I extend my C drive even though there is unallocated space?

Windows can only extend C drive if unallocated space is immediately to its right. Partitions or recovery partitions in between will block the extension.

Can I extend C drive safely without losing data?

Yes. Using IM-Magic Partition Resizer Free, you can safely extend C drive without losing files.

Is IM-Magic Partition Resizer Free safe to use?

Yes. It safely resizes, moves, and extends partitions, including system partitions, using pre-OS mode for locked areas.

Why is the 'Extend Volume' option greyed out?

It is usually greyed out because unallocated space is not adjacent to C, recovery partitions block the way, the disk is FAT32, or the disk is MBR with partition limits.