You can refer to this post to learn what is primary partition, extended partition, and can extended partition be bootable.
My computer has three primary partitions and one extended partition, one primary partition is used to install Windows 7, and the other two primary partitions are used to store data. I want to install Windows 10, but I don’t want to install it on the primary partition where the data is stored. So I just installed it on the extended partition. I'm not sure if Windows OS can be installed on an extended partition? Are extended partition bootable? If not, how can I fix it?
To know can extended partition be bootable. First of all, you need to have a basic understanding of disk partition. Primary partition and extended partition are based on the concept of MBR disk. An MBR disk can contain up to 4 primary partitions, or 3 primary partitions and an extended partition. There is no such concept on GPT disks. All partitions on GPT disks are primary partitions.
Tip: Click What’s the Difference Between GPT and MBR Partition Style to know more information about MBR and GPT.
✍ Primary Partition: The primary partition is the bootable partition that contains the computer's operating system, and the primary partition provides the necessary elements for the operating system. The active partition is based on the primary partition, and any of the 4 primary partitions can be set as the active partition. ✍ Extended partition: The extended partition is a non-bootable partition, operating system bootable file can not be reside in the extended partition. Besides, the extended partition cannot be used directly, it is used as a logical partition. It is similar to a container and can hold multiple logical partitions. Within an extended partition, you can create an unlimited number of (Windows supports up to 128) logical partitions. If the extended partition is no longer partitioned, the entire extended partition is a logical partition. ✍ Logical partition: A logical partition is a partition created within an extended partition. Most of the time, logical partitions are only used to store personal data because Windows cannot boot from logical partitions. When you need to prepare a partition for the system or boot, you can convert the logical partition to primary.
In addition to converting logical partition to primary partition, you can also convert MBR disk to GPT. Because GPT disks do not have extended partitions and all partitions are primary partitions, it is a good choice to use GPT disks to install dual operating systems.
To do this, I highly recommend you to use AOMEI Partition Assistant Professional. This is a GUI disk partition manager which is loved by market. It can help you convert system/data disk from MBR to GPT without losing data, users can do it with a few clicks. Please download the Demo version to see how it works.
Note: Before converting the system disk from MBR to GPT, you should make sure whether your motherboard supports UEFI boot mode. Otherwise, the computer will not boot from it.
Step 1. Download and install AOMEI Partition Assistant Professional. Then, run it.
Step 2. Right-click the system disk and select Convert to GPT.
Step 3. Read the prompt and click Yes.
Step 4. Click Apply to submit the operations.
After your PC has successfully booted from UEFI, you can install a new Windows system on either partition.
Can extended partition be bootable? After reading this article, I believe you already know the extended partition cannot be used as a boot partition. If you want to install the dual system on your PC, you can convert the extended partition to the primary partition or convert the MBR disk to GPT with the help of the AOMEI Partition Assistant Professional.