So I have a 3TB HDD and since I have got it, it has always shown 2TB. I assumed I got the wrong hdd, however looking in disc manager, I do not, there is 746.52gb unallocated, I cannot allocate it, so I looked it up, I have to make the drive GPT instead of MBR, but I already have almost 2TB of stuff on there that cannot lose access to, and I need to be able to allocate that other 1tb I cant access. Is there a way to convert the HDD from MBR to GPT without data loss? I might have to find multiple hard drives from old laptops to temporarily store data but I really do not want to do that, any ideas?
![]() |
There are isolated problems with current patches, but they are well-known and documented on this site. |
SIGN IN | Not a member? | REGISTER | PLUS MEMBERSHIP |
-
Convert HDD Partition Type Without Data Loss
Home » Forums » AskWoody support » PC hardware » Questions – Maintenance and backups » Convert HDD Partition Type Without Data Loss
- This topic has 9 replies, 9 voices, and was last updated 5 years, 10 months ago.
Viewing 6 reply threadsAuthorReplies-
RetiredGeek
AskWoody_MVPJuly 2, 2019 at 5:42 am #1865187Martin,
I’ve used EaseUS Partition Master Free to do this several times w/o issue.
Of course, it’s still a very good idea to have a backup JIC! YMMV.
HTH
-
This reply was modified 5 years, 11 months ago by
RetiredGeek.
1 user thanked author for this post.
-
This reply was modified 5 years, 11 months ago by
-
GoneToPlaid
AskWoody LoungerJuly 2, 2019 at 10:14 pm #1866128Yeah, it works. I am not too keen about the telemetry in EaseUS products. Nothing nefarious. I have to admit that EaseUS Partition Master is straightforward to use, and that it has been bulletproof for me as well. Run it only after having run a Scandisk and confirming that there are no errors on the hard drive’s partition(s). If you are paranoid about telemetry, simply uninstall it after using it. It does uninstall cleanly.
-
-
mngerhold
AskWoody LoungerJuly 2, 2019 at 5:50 am #1865195stuff on there that cannot lose access to
I would say the first thing you should do is purchase a backup external drive – I know RG mentioned backup, but do that first! You may prefer to trust the cloud (I wouldn’t).
-
anonymous
Guest -
jabeattyauditor
AskWoody LoungerJuly 2, 2019 at 10:11 am #1865454Windows 10 has a native conversion tool now – mbr2gpt. You can only run it from the recovery environment or install media though.
Looks like you can now run it from the running OS (1703 or higher) natively using the /allowFullOS option.
There’s a long list of caveats at the site noted in cmptrgy’s post.
1 user thanked author for this post.
-
-
cmptrgy
AskWoody LoungerJuly 2, 2019 at 10:03 am #1865453Windows 10 has a native conversion tool now – mbr2gpt. You can only run it from the recovery environment or install media though.
MBR2GPT.EXE
https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt
MBR2GPT.EXE converts a disk from the Master Boot Record (MBR) to the GUID Partition Table (GPT) partition style without modifying or deleting data on the disk.HP EliteBook 8540w laptop Windows 10 Pro (x64)
-
cmptrgy
AskWoody LoungerJuly 2, 2019 at 8:39 pm #1866076Windows 10 has a native conversion tool now – mbr2gpt. You can only run it from the recovery environment or install media though.
Looks like you can now run it from the running OS (1703 or higher) natively using the /allowFullOS option.
There’s a long list of caveats at the site noted in cmptrgy’s post.
Actually now that I’ve had time to compare them I like RetiredGeek’s recommendation in post #1865187
HP EliteBook 8540w laptop Windows 10 Pro (x64)
-
Alex5723
AskWoody Plus -
rc primak
AskWoody_MVPJuly 8, 2019 at 4:37 am #1871430Also useful and successful for me is Minitool Partition Wizard:
Windows 10 does indeed have in its Disk Management or DiskPart tools the ability to make this conversion.
As posted above, these methods do carry some risk. I would make a backup first, but then again I have like a million spare hard drives lying around my place.
-- rc primak
1 user thanked author for this post.
Viewing 6 reply threads -

Plus Membership
Donations from Plus members keep this site going. You can identify the people who support AskWoody by the Plus badge on their avatars.
AskWoody Plus members not only get access to all of the contents of this site -- including Susan Bradley's frequently updated Patch Watch listing -- they also receive weekly AskWoody Plus Newsletters (formerly Windows Secrets Newsletter) and AskWoody Plus Alerts, emails when there are important breaking developments.
Get Plus!
Welcome to our unique respite from the madness.
It's easy to post questions about Windows 11, Windows 10, Win8.1, Win7, Surface, Office, or browse through our Forums. Post anonymously or register for greater privileges. Keep it civil, please: Decorous Lounge rules strictly enforced. Questions? Contact Customer Support.
Search Newsletters
Search Forums
View the Forum
Search for Topics
Recent Topics
-
KB5058379 / KB 5061768 Failures
by
crown
1 hour, 11 minutes ago -
Windows 10 23H2 Good to Update to ?
by
jkitc
1 hour, 19 minutes ago -
At last – installation of 24H2
by
Botswana12
2 hours, 4 minutes ago -
MS-DEFCON 4: As good as it gets
by
Susan Bradley
23 minutes ago -
RyTuneX optimize Windows 10/11 tool
by
Alex5723
14 hours, 16 minutes ago -
Can I just update from Win11 22H2 to 23H2?
by
Dave Easley
7 hours, 35 minutes ago -
Limited account permission error related to Windows Update
by
gtd12345
1 day, 3 hours ago -
Another test post
by
gtd12345
1 day, 3 hours ago -
Connect to someone else computer
by
wadeer
22 hours, 15 minutes ago -
Limit on User names?
by
CWBillow
1 day, 1 hour ago -
Choose the right apps for traveling
by
Peter Deegan
15 hours, 15 minutes ago -
BitLocker rears its head
by
Susan Bradley
23 hours, 50 minutes ago -
Who are you? (2025 edition)
by
Will Fastie
1 hour, 5 minutes ago -
AskWoody at the computer museum, round two
by
Will Fastie
17 hours, 38 minutes ago -
A smarter, simpler Firefox address bar
by
Alex5723
1 day, 14 hours ago -
Woody
by
Scott
1 day, 23 hours ago -
24H2 has suppressed my favoured spider
by
Davidhs
22 hours, 55 minutes ago -
GeForce RTX 5060 in certain motherboards could experience blank screens
by
Alex5723
2 days, 13 hours ago -
MS Office 365 Home on MAC
by
MickIver
2 days, 7 hours ago -
Google’s Veo3 video generator. Before you ask: yes, everything is AI here
by
Alex5723
3 days, 3 hours ago -
Flash Drive Eject Error for Still In Use
by
J9438
2 hours, 40 minutes ago -
Windows 11 Insider Preview build 27863 released to Canary
by
joep517
3 days, 22 hours ago -
Windows 11 Insider Preview build 26120.4161 (24H2) released to BETA
by
joep517
3 days, 22 hours ago -
AI model turns to blackmail when engineers try to take it offline
by
Cybertooth
3 days, 2 hours ago -
Migrate off MS365 to Apple Products
by
dmt_3904
3 days, 3 hours ago -
Login screen icon
by
CWBillow
2 days, 17 hours ago -
AI coming to everything
by
Susan Bradley
8 hours, 6 minutes ago -
Mozilla : Pocket shuts down July 8, 2025, Fakespot shuts down on July 1, 2025
by
Alex5723
4 days, 14 hours ago -
No Screen TurnOff???
by
CWBillow
4 days, 14 hours ago -
Identify a dynamic range to then be used in another formula
by
BigDaddy07
4 days, 15 hours ago
Recent blog posts
Key Links
Want to Advertise in the free newsletter? How about a gift subscription in honor of a birthday? Send an email to sb@askwoody.com to ask how.
Mastodon profile for DefConPatch
Mastodon profile for AskWoody
Home • About • FAQ • Posts & Privacy • Forums • My Account
Register • Free Newsletter • Plus Membership • Gift Certificates • MS-DEFCON Alerts
Copyright ©2004-2025 by AskWoody Tech LLC. All Rights Reserved.