About the unallocated space after Windows 10 upgrade
After free upgrade to Windows 10 from Windows 7/8.1,
mysteriously they lost a partition, which is shown as unallocated space in Disk
Management. 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, the space beyond 2TB
becomes unallocated space, leaving you no options to utilize this space. If
you look deep into it, you may find out that this hard drive has been miraculously
converted to MBR partition table from GPT. 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 space after Windows upgrade?
If your hard drive was GPT previously, you can also convert MBT to GPT without data
loss by using third party software, such as AOMEI Partition Assistant.
To convert MBR to GPT without affecting OS:
1. Download and run AOMEI Partition Assistant
2. At its main interface, you can see the all the disks and partitions status. Right
click on the disk that lost space and select “Convert to GPT disk”.
4. Then you can right click on the unallocated space and create a new partition or
you can merge the unallocated space to other partitions by using “Merge Partitions” function.
5. After that, click “Apply” to save all these changes.
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 MSR 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.