About extended partition
An extended partition is referring to master boot record (MBR) disks. On an MBR disk,
you can have 4 primary partitions or less than 4 primary partitions and 1 extended
partition. Within the extended partition, you can create many logical partitions as
you need. The only limit to the number of logical partitions is the available drive
letters that you can use. If there is unallocated space within the extended
partition as the screenshot below, you cannot use it to extend or create a primary
partition with Windows built-in utility Disk Management, though you only have 1 or 2
primary partitions.

You need to move unallocated outside extended partition in order to extend or create
a primary partition. However, Disk Management doesn’t have the ability to move
partition, in this situation, so you need to delete all the extended partition,
namely all the logical partitions before you can extend or create a primary
partition unless you try a third party partition software.
How to move unallocated space from extended partition?
AOMEI Partition Assistant Standard is a free partition manager software that allows
you to move unallocated space from extended to primary without data loss. If you
want to create a new primary partition, just use the Move Partition feature. Let’s
see how it works:
1. Free download AOMEI Partition Assistant, install
and launch it.
2. With its concise main interface, right-click on the logical partition that is in
the way between primary partition and the unallocated space you want to move, and
then select “Move Partition”

3. In the next screen, click on the logical partition, and drag it to the right so
that the unallocated space can be moved to the left. If there are more than one
logical partitions between them, use this steps to move them one by one.

4. Click on “Apply” in the toolbar to execute all operations to your disk. The
program allows you to preview the partition layout without making any changes to
your disk to avoid any mistaken operations.

Then the program will move the extended partition rightwards, so you can use the
unallocated space to create or extend a primary partition. When using the
unallocated space out of extended partition to create a new partition, it will be
created as a primary partition by default. If you want to add the unallocated space
within the extended partition to a primary partition, you can just use the Merge Partitions feature, which will
automatically move the unallocated space out of extended partition and add it into
the primary partition. If you just want to create a primary partition regardless of
its location, you can also use AOMEI Partition Assistant to directly create a
primary partition using the free space in the extended partition without the need to
move space between partitions.
Create primary partition directly
Unlike Disk Management or other disk partition management tools, AOMEI Partition
Assistant can create a primary partition in the extended partition, as long as there
are no more than 2 primary partitions existing on the disk. The steps are very
simple, which is shown as below:
1. With the main interface of AOMEI Partition Assistant open, right-click on
unallocated space within the extended partition, and choose Create Partition.

2. At the pop-out screen, to specify the partition size. Click the Advanced option,
select Create as Primary Partition. If you want to adjust partition size, just drag
the slider or enter the amount of space in the Partition Size box. Then click OK to
proceed.

3. As before, just click Apply to run the operations if no problems.
If your computer supports UEFI boot, AOMEI Partition Assistant also can convert MBR to GPT disk without data
loss, so you don’t have to move unallocated outside extended partition for more
primary partitions. Besides the features mentioned above, AOMEI Partition Assistant
enables you to convert NTFS to FAT32 without data loss, create bootable media, migrate OS
to SSD, and many more.