Resolve "Unallocated Space Cannot Create Partition" Issue in Disk Management [Windows 7/8/10/11]

Partitions refer to the way we divide our hard disk storage into multiple sections. However, you might occasionally observe that the partition you've created doesn't utilize the entire storage space, leaving some unallocated space behind.

When attempting to create a new partition using Disk Management for the unused space, you might encounter the "unallocated space cannot create partition" error. Continue reading to gain more insights into this issue and discover how to resolve it.

Why Can't I Create a Partition on Unallocated Space?

There are numerous reasons why Windows displays the "unallocated space cannot create partition" error. These reasons can span from issues with the hard disk's format and size to problems with USB and external devices. We have outlined the three most common causes behind Windows' inability to create a partition for unallocated space:

1. The Format of Hard Disk (MBR/GPT)

The two most commonly used formats for hard disks are MBR (Master Boot Record) and GPT (GUID Partition Table). In over 80% of cases, this error occurs due to the hard disk being formatted as MBR. MBR supports hard drives up to 2TB in size and permits only four partitions (three primary + one extended). In contrast, GPT can accommodate hard drives larger than 2TB and allows an unlimited number of partitions.

2. Connected Peripheral Devices

Another reason for "unallocated space cannot create partition" errors might be the peripheral devices connected to your system. Occasionally, Windows may recognize these devices as default hard disks, preventing you from creating a new partition, particularly if your hard drive is in MBR (Master Boot Record) format. To resolve this, disconnect all peripheral devices and then attempt to create a new partition.

3. Unable to Create Inactive Partitions

There is also a possibility that you cannot create a specific partition because it is not marked as active. An active partition designates the location of the operating system. When a partition is inactive, your system will be unable to boot from that particular operating system. To proceed with creating the partition, you will first need to activate the desired partition.

How to Resolve "Unallocated Space Cannot Create Partition"

There are various approaches to resolve the "unallocated space cannot create partition" error on your Windows system. Some methods can be executed directly within the Windows operating system, while others require the assistance of trustworthy third-party software. This article will delve into four of the most common and effective methods to address the issues preventing the creation of new partitions in Windows.

Method 1: Convert MBR to GPT

Since the most common issue behind the "unallocated space cannot create partition" error is the MBR disk format, it's advisable to convert it to GPT. You can do this on Windows using the Disk Management utility, but be aware that this process will erase all data on your hard drive. To prevent data loss, we recommend using a reliable and tested tool like tools Partition Master. This tool allows you to convert your hard disk from MBR to GPT without losing any data or deleting any partitions.

The process to convert MBR to GPT in Partition Master is straightforward and concise. To change your hard disk from MBR to GPT, follow these steps: 1. **Launch Partition Master Tool**: First, download and install the Partition Master software on your computer. Make sure it's the appropriate version for your operating system. 2. **Boot into the Software**: After installation, launch the Partition Master tool. If you're using the desktop version, it will open directly. If you're using the bootable media, restart your computer and access the tool from the boot menu. 3. **Select the Hard Disk**: In the main interface of Partition Master, you'll see a list of all the storage devices connected to your PC. Identify the hard disk you want to convert and select it. 4. **Check Disk Information**: Before proceeding, verify that the selected hard disk is currently using the MBR partition style. This information is usually displayed next to the disk name or in the properties section. 5. **Convert MBR to GPT**: Look for an option like "Convert MBR to GPT" or "Disk -> Convert to GPT Disk." Click on it, and a confirmation prompt may appear. Read the warning message carefully, as converting to GPT will erase all data on the disk. 6. **Backup Data**: If you haven't already done so, backup any important data on the hard disk to an external storage device, as the conversion process will wipe the disk. 7. **Confirm Conversion**: After ensuring your data is safe, click "OK" or "Proceed" to start the conversion process. The tool will then initiate the conversion from MBR to GPT. 8. **Wait for Completion**: This process might take some time depending on the size of your hard disk. Do not interrupt the process or turn off your computer during this time. 9. **Verify the Conversion**: Once the conversion is complete, Partition Master will display the updated disk information, now showing that the hard disk is using the GPT partition style. 10. **Restart Your Computer**: Finally, restart your computer for the changes to take effect. Your hard disk should now be in the GPT format. Remember, always exercise caution when making changes to your disk partitions, and ensure you have backups of crucial data.

Step 1. Download and launch tools Partition Master on your computer.

Step 2. Proceed to Disk Converter, choose "Convert MBR to GPT," and click "Next" to proceed.

Step 3. Select the target MBR disk that you want to convert to GPT and click "Convert" to start the process.

Converting MBR to GPT during Windows installation using Partition Master is a simple and efficient solution to resolve the "unallocated space cannot create partition" error. Additionally, Partition Master can also address other issues related to MBR.

• Rebuilding corrupted MBR
• Convert dynamic disk to basic and conversely
• Initialize unallocated, unknown, or uninitialized disks as MBR or GPT
• Delete partitions or securely erase them to render data unrecoverable

MiniTool Partition Wizard is an excellent disk partition tool. Download it and you can enjoy the convenience it brings to your computer!

Method 2: Disconnect External Drives

One of the main reasons for the inability to create new partitions is the presence of connected external devices such as USB drives, external storage devices, etc. If you are installing a new version of Windows, make sure to disconnect all peripheral devices from your system except for the USB drive used to boot Windows. However, if you are attempting to create a partition within Windows itself, follow these steps to disconnect your external devices: 1. **Save and Close Open Programs**: First, ensure that all programs and files on your system are closed to prevent any data loss. 2. **Disconnect USB Devices**: Physically unplug any USB devices, including flash drives, external hard drives, or other storage peripherals. 3. **Eject External Storage**: For external storage devices like external hard drives, right-click on their icon in the "This PC" (previously known as "My Computer") window and select "Eject." This ensures that Windows safely removes the device, preventing any potential damage to the data. 4. **Remove Bluetooth Devices**: If you have any Bluetooth devices connected, go to your system's Bluetooth settings and disconnect them. 5. **Disable Hardware in Device Manager**: In case any devices still show up in Device Manager even after being unplugged, you can disable them temporarily. Press 'Windows key + X' and choose 'Device Manager.' Locate the external devices, right-click on them, and select 'Disable device.' 6. **Create Partition**: Now, with all external devices disconnected or disabled, you should be able to create a new partition through the Windows Disk Management tool. To access it, right-click on the Start button, select 'Disk Management,' and proceed with creating a new partition. Remember to reconnect your devices once the partition process is complete.

Step 1: Locate the external device by opening "My Computer" and right-clicking on the external device.

Step 2: Right-click on the external device and select "Eject" to safely remove it from your system.

方法3：创建新分区

There's also a direct method to create a partition if you can't do it manually. For this, you'll need to use a third-party tool. Tools like AOMEI Partition Assistant are an all-in-one solution for any issues related to partitions on hard drives. It supports creating a partition from unallocated space to replace Disk Management. You can refer to this guide: create partition from unallocated space.

On Windows, you can also use the Diskpart command to create new partitions. However, the operation is more complex, so be cautious when typing the commands.

Method 4: Make Partition Active

An active partition refers to a partition on a hard drive that contains an operating system. Typically, there is only one active partition on a system. However, it is feasible to have multiple partitions with different operating systems within a single system. In such scenarios, you must designate one partition as active, as this allows the system to load the operating system from that particular partition during bootup.如果没有激活的分区，系统将无法在启动后加载。

Tools Partition Master offers a swift and user-friendly method to activate your desired partition. The "Set Active" feature provides a one-click solution for creating an active partition, thereby preventing Windows boot failure errors. It's advisable to format the disk before activating it to ensure that it solely contains the operating system.

Conclusion

The unallocated space on your hard drive represents a wasteful use of crucial resources. Your primary goal should be to optimize the utilization of your hard drive space. If you encounter errors such as "unallocated space cannot create partition" while attempting to create new partitions from unallocated space, Partition Master is the ideal solution. It is adept at addressing all issues and errors related to partitions in your system.

FAQ: Unable to Create Partition with Unallocated Space

The article comprehensively addresses all significant queries concerning the "unallocated space cannot create partition" error in Windows. Should you have any additional questions, we have also provided answers to frequently asked questions found online.

1. How do I convert unallocated space into a partition?

You can convert the unallocated space into a partition by using the Disk Management utility in Windows. Upon opening it in a new window, select the hard drive you wish to extend and right-click on it, then choose the "Extend Volume" option. Proceed to follow the on-screen instructions to create a partition utilizing the unallocated space.

2. How do I fix an unallocated hard drive partition? To fix an unallocated hard drive partition, follow these steps: 1. **Open Disk Management**: Press `Win + X` on your keyboard and choose "Disk Management" from the menu, or right-click the Start button and select it. 2. **Locate the Unallocated Space**: In the Disk Management window, look for the unallocated partition, which will be displayed as a black area without a drive letter. 3. **Create a New Partition**: Right-click on the unallocated space and select "New Simple Volume." 4. **New Simple Volume Wizard**: Follow the prompts in the New Simple Volume Wizard: - Click "Next" to start. - Assign a drive letter or accept the default one suggested. - Choose the volume size (usually recommended to use all available space). - Select the file system (NTFS is the most common for Windows) and set the allocation unit size (default is usually fine). - Finish the wizard by clicking "Finish." 5. **Format the Partition**: After creating the new partition, it may not be usable until formatted. Right-click the new partition and choose "Format." - Choose the file system (NTFS is recommended), allocation unit size, and give the volume a label if desired. - Click "OK" to format the partition, but be aware that this will erase any existing data. 6. **Wait for the Process to Complete**: Formatting might take some time, depending on the size of the partition. Wait for it to finish before using the new partition. 7. **Verify the Partition**: Once complete, the new partition should be visible in File Explorer with the assigned drive letter. You can now use it to store files and data. If you still encounter issues, you might need to consider using third-party disk management tools like MiniTool Partition Wizard or AOMEI Backupper for more advanced options.

To resolve an unallocated drive partition, you can either delete and recreate it or attempt to update your disk drivers. When eliminating the unallocated partition, utilize the Diskpart tool to select the partition and delete it. Subsequently, you can create a new partition using Diskpart. It's also possible that outdated drivers are causing the hard drive partition to become unallocated. Update the drivers and see if the issue is rectified.

3. Why can't I extend the C drive with unallocated space?

In general, Windows does not permit extending the C drive or any other primary drive using the "Extend Volume" feature when unallocated space is present. To expand the C drive partition or any other primary drive, you would typically require reliable third-party software such as Partition Master.