About the unallocated space after Windows 10 upgrade
After free upgrading to Windows 10 from Windows 7/8.1, you might find you lost a partition, which is shown as unallocated space in Disk
Management. How did this happened?
Nowadays, many users have installed large hard drive over 2TB in the
computer in order to store all the important stuff. If you are using over 2TB hard
drive with MBR partition style, the space beyond 2TB becomes unallocated space, leaving you no options to utilize this space.
MBR disks support up to 2TB capacity,
which is why you cannot use the unallocated space to create a new partition or merge
into other partitions on the same disk. If you hard drive is less than 2TB and you
still lost one partition, that is because your MBR disk has 4 primary partitions,
and Windows 10 created a recovery partition by shrinking the C drive during the
upgrade. On MBR disk, there can only be at most 4 primary partitions, so the last
partition on your hard drive get deleted.
How to reclaim unallocated space after Windows upgrade?
So, to reclaim the unallocated space, you might need to employ a partition style converter to change the MBR disk to GPT, which supports much larger partition space (up to 9.4ZB). And you can turn to AOMEI Partition Assistant Professional that can help you to convert MBR to GPT without data loss
And you can download the demo version and follow the steps below to have a try.
Open AOMEI Partition Assistant, and right click on the system disk, and choose "Convert to GPT".
2. Ensure the motherboard supports UEFI boot mode, and click "OK" > "Yes".
3. And click "Apply" > "Proceed" to commit the operation.
After converting the system disk to GPT disk, AOMEI Partition Assistant can also help you to create a new partition on the unallocated space, or merge the unallocated space with other partitions.
All these operation can be undone before you click the “Apply” button, and the
process will be complete in AOMEI PreOS mode after a reboot. If your hard drive was
MBR, you can delete the recovery partition by creating a Windows
10 recovery drive. Also, you can still use AOMEI Partition Assistant to
directly create a logical
partition with the unallocated space. It will automatically convert the last
partition on the hard drive into logical partition.
How to avoid windows 10 unallocated space being generated?
If your hard drive is GPT, which contains an EFI system
partition and MBR partition, then your computer has UEFI support. Most of the
UEFI computers support compatible Legacy BISO based boot mode which allows you to
boot from an MBR disk. If you enable both UEFI and Legacy mode, Windows may
mistakenly take Legacy mode, and then convert your hard drive to MBR. Therefore, to
prevent this, you can make sure you only use UEFI mode by disable Legacy mode.
If your hard drive is MBR, you can convert one of your partition to logical
partition, then should not lose a partition during the Windows 10 upgrade. There is
also another way to avoid the problem that a partition become unallocated. Windows
10 recovery partition upgrade will only be created when it detects the
system reserved partition or recovery partition (if you have one) has insufficient
space. Therefore, you can also extend the system reserved partition before upgrade
to Windows 10.
No matter what situations you are in, you can use AOMEI Partition Assistant to help
you manage the unallocated space after Windows 10 upgrade problem. Besides, it also
has many powerful featuers including OS
Migration, Dynamic Disk Converter, and Windows 8/10 to Go Creator.