Running out of space on your C drive is one of the most frustrating problems on a Windows PC. You open Disk Management, see a big chunk of unallocated space, and think the fix will take 5 seconds… but then Windows refuses to extend the C drive. The “Extend Volume” option is greyed out, and nothing works.
This isn’t a bug — it’s a limitation of how Windows handles partitions.
Windows can only extend a partition if the unallocated space is placed directly next to it. In many systems, a hidden Recovery partition sits between the C drive and the unallocated space. Even though the space is available, Windows treats that recovery partition as a wall and blocks the extension.
The good news? You don’t need third-party software, cracked tools, or risky partition apps. Windows already includes the tools required to fix this safely — you just need to follow the steps in the correct order.
In this guide, you’ll learn:
- Why Windows refuses to extend the C drive
- What the Recovery partition actually does
- How to temporarily disable it safely
- How to extend your C drive properly
- How to recreate and re-enable the Recovery partition afterward
Everything is explained step-by-step in beginner-friendly language. If you follow carefully, you’ll unlock that unallocated space and give your C drive the storage it deserves — without breaking Windows.
⚠️ Important: This process modifies disk partitions. Back up important files before continuing. While the method is safe when followed correctly, mistakes in DiskPart can affect other partitions.
Ready? Let’s fix
Step 1 — Understand Why the C Drive Can’t Be Extended
Before we start fixing anything, it’s important to understand why Windows is blocking the extension in the first place. Once you see the logic behind it, the solution makes perfect sense.
Open Disk Management:
- Press Windows + X
- Click Disk Management
Look at the layout of your disk carefully.
Most users will see something like this:
[C Drive] → [Recovery Partition] → [Unallocated Space]
Here’s the key rule:
Windows can only extend a partition into unallocated space that is directly next to it on the right.
Even if you have 200GB of free unallocated space, Windows refuses to extend C: because the Recovery partition is sitting in between. Disk Management does not know how to “move” partitions — it can only extend into adjacent space.
That tiny Recovery partition is the problem.
What is the Recovery Partition?
The Recovery partition is a hidden Windows system partition that stores:
- Windows Recovery Environment (WinRE)
- Startup repair tools
- Reset and recovery options
It’s useful, but it sometimes blocks disk resizing. The trick is not to permanently remove it — we will:
- Temporarily disable it
- Remove it
- Extend the C drive
- Recreate it properly
This keeps your system safe while unlocking the storage.
Step 2 — Disable Windows Recovery Environment
We must disable WinRE before deleting the Recovery partition. This tells Windows not to rely on it temporarily.
- Search cmd
- Right-click Command Prompt
- Choose Run as administrator
Type the following command:
reagentc /disable
Press Enter.
If successful, Windows will confirm that the recovery environment is disabled.
You can verify status with:
reagentc /info
It should show:
Windows RE status: Disabled
Now Windows won’t depend on the Recovery partition, which means we can safely remove it in the next step.
Next, we’ll use DiskPart to delete the partition that’s blocking your C drive.
Step 3 — Delete the Recovery Partition Blocking the C Drive
Now that WinRE is disabled, we can remove the small Recovery partition that’s preventing Windows from extending the C drive.
We’ll use DiskPart, which is Microsoft’s built-in disk management tool. Be careful and follow each step slowly — selecting the wrong partition can delete the wrong data.
You should still have the admin Command Prompt open.
3.1 — Open DiskPart
Type:
diskpart
Press Enter
You’ll now see:
DISKPART>
This means DiskPart is active.
3.2 — Select the Correct Disk
List available disks:
list disk
Most systems only have one disk, usually:
Disk 0
Select it:
select disk 0
3.3 — List All Partitions
Now show partitions:
list partition
You’ll see a numbered list like:
Partition 1 System
Partition 2 Reserved
Partition 3 Primary (C:)
Partition 4 Recovery
The Recovery partition is typically:
- 500MB to 1GB
- labeled Recovery
- located between C: and Unallocated space
3.4 — Select the Recovery Partition
Example (yours may be a different number):
select partition 4
Double-check details before deleting:
detail partition
Confirm it is the Recovery partition — not your C drive.
3.5 — Delete the Recovery Partition
Once confirmed, run:
delete partition override
This forces deletion of protected partitions.
After this step, the Recovery partition disappears and becomes unallocated space.
Now the unallocated space is directly next to the C drive.
That means Windows will finally allow extension.
Next, we’ll extend the C drive using Disk Management.
Step 4 — Extend the C Drive Into the Unallocated Space
Now that the Recovery partition is gone, the unallocated space should be sitting directly next to the C drive. This is the exact condition Windows requires in order to extend a partition.
This part is easy — no commands needed.
4.1 — Open Disk Management Again
- Press Windows + X
- Click Disk Management
You should now see:
[C Drive] → [Unallocated Space]
If that’s the case, you’re ready.
4.2 — Extend the C Drive
- Right-click the C drive
- Click Extend Volume
- The Extend Volume Wizard opens
- Click Next
- Select the available unallocated space
- Click Next
- Click Finish
Windows will merge the unallocated space into C:.
Within a few seconds, your C drive should show the new, larger size.
No restart required.
At this point, your storage problem is fixed — but we’re not done yet.
We still need to recreate the Recovery partition so Windows recovery tools continue working properly.
Step 5 — Recreate the Windows Recovery Partition
We removed the Recovery partition to unblock the C drive. Now we’ll recreate it properly so Windows recovery tools keep working.
This step is important — skipping it means you lose reset/repair options.
5.1 — Create 1GB of Unallocated Space
If you used all space for C:, you need to shrink it slightly.
- Open Disk Management
- Right-click C drive
- Click Shrink Volume
- Enter:
1024 MB
- Click Shrink
You now have ~1GB unallocated space at the end of the disk.
5.2 — Open DiskPart Again
Back in admin Command Prompt:
diskpart
Then:
list disk
select disk 0
5.3 — Create the New Recovery Partition
Create a 1GB partition:
create partition primary size=1024
List partitions:
list partition
Select the new partition (example):
select partition X
(Replace X with your new partition number)
5.4 — Set Recovery Partition Type
Most modern PCs use GPT disks (Windows 10/11 standard).
Run:
set id=de94bba4-06d1-4d40-a16a-bfd50179d6ac
gpt attributes=0x8000000000000001
If your disk is MBR instead, use:
set id=27
5.5 — Hide the Partition (Remove Drive Letter)
Sometimes Windows assigns a drive letter.
Remove it:
list volume
select volume X
remove letter=X
exit
Now the Recovery partition is hidden again.
Next step: re-enable Windows Recovery Environment so everything works normally.
Step 6 — Re-Enable Windows Recovery Environment (Final Step)
We recreated the Recovery partition. Now we just need to tell Windows to use it again.
This restores:
- Startup Repair
- Reset this PC
- Advanced recovery options
- WinRE tools
6.1 — Enable WinRE
Open Command Prompt as administrator and run:
reagentc /enable
Press Enter
Windows should confirm:
Operation successful
6.2 — Verify Recovery Status
Run:
reagentc /info
You want to see:
Windows RE status: Enabled
That means recovery is working again.
✅ Done — Your C Drive Is Extended Safely
At this point you have:
✔ A larger C drive
✔ Proper Recovery partition restored
✔ Windows recovery tools enabled
✔ No third-party software used
✔ No system damage
Your storage is fixed the correct way.
Final Words
This method fixes the most common Windows storage limitation without risky software or hacks. You temporarily removed a blocking partition, extended the C drive properly, and rebuilt recovery exactly the way Windows expects.
If you want, you can send a screenshot of your Disk Management layout and I’ll double-check everything for you before you run the commands.
