1 Topic by 1319shd

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Topic: Partition Table Type MSDOS

I booted my PC to linux using a USB.  From GParted, I went to the Device menu, Create Partition Table,  and I changed it to MSDOS.  The original partition table type was GPT.

Now, all of my partitions are gone and I only see an unallocated partition.  How can I recover my 3 partitions and their data please?

I have tried Testdisk, but it said that those partitions are not recoverable.

Any thoughts please?  All I wanted to do was to have a clean install of Microsoft Windows 10 Creator Update.

2 Reply by class413

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Re: Partition Table Type MSDOS

Changing the partition type isn't possible by GParted. The old partition table is overwritten by the new one and the previous disk content isn't accessible anymore.

Testdisk tries to detect the limits of old partitions. This can be successful if nothing else was done on the disk space. Any further operation on the drive will decrease recovery possibilities. There is a backup copy of the GUID partition table data at the end of the disk space (secondary GPT). If the primary GPT is accidentally broken, it could be restored from the secondary GPT. If the secondary GPT is overwritten too, there are less recovery chances. If you want to recover the HD data, you have to use file recovery software. "photorec" is such a free software, however the recovery work isn't easy.

To install any Microsoft Windows 10 software/component, please check if UEFI BIOS lock is needed to be activated.

*** It is highly recommended to backup any important files before doing resize/move operations. ***

3 Reply by mfleetwo

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Re: Partition Table Type MSDOS

@1319shd
Unfortunately as class413 said GParted doesn't change partition table types, it removes the old partition table and writes a new partition table.  That is why the Create Partition Table dialog says the following in large bold letters:

  WARNING: This will ERASE ALL DATA on the ENTIRE DISK


https://i.postimg.cc/50LT0t5Y/gparted-forum-thread-17674-picture-1-create-part.png


Just to update what  class413 said about the secondary GPT being available.  GParted is very likely to have erased both the primary GPT at the start and the secondary GPT at the end of the disk.  It writes 512K of zero to the start and end (last whole 512K) of the disk to ensure that old signatures are erased before new partition tables, or file systems within partitions, are written to prevent all sorts of tools getting confused by detecting multiple different signatures.


As class413 said, testdisk was your best option to re-discover the original partition boundaries.

After that you will have to start manually guessing partition boundaries, using GPT and file system tools and possibly even hex editors looking for the file systems.  Alternatively you might be able to find a profession service which can recover the data for you.  I have never tried one or even looked for one.

4 Reply by 1319shd

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Re: Partition Table Type MSDOS

Thank you!  So should I convert msdos to gpt and run that software?  What is the best action right now?  Because gparted shows that as unallocated

When I wanted to install Windows, it said that it can't install it on a gpt partition.

In bios, I had to disable uefi, and activated legacy boot.

5 Reply by 1319shd (edited by 1319shd 2017-09-08 22:01:15)

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Re: Partition Table Type MSDOS

Thank you!  So should I convert msdos to gpt and run testdisk software?  What is the best action right now?  Because gparted shows that as unallocated

6 Reply by 1319shd

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Re: Partition Table Type MSDOS

What should  I do with this please?

TestDisk 7.0, Data Recovery Utility, April 2015
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sda - 1000 GB / 931 GiB - CHS 121601 255 63

The harddisk (1000 GB / 931 GiB) seems too small! (< 13658652 TB / 12422472 TiB)
Check the harddisk size: HD jumpers settings, BIOS detection...

The following partitions can't be recovered:
     Partition               Start        End    Size in sectors
>  MS Data                 92022991 26677055726168271 26677055634145280 [^A]
   MS Data                344027814 15253227632764769 15253227288736955 [s (%d substripes) of %lx)
   MS Data                344167845 15253227632904800 15253227288736955 [s (%d substripes) of %lx)
   MS Data               1926657853 3850923836 1924265984
   MS Data               1927681822 3243640574 1315958753
   MS Data               1927681853 3243640605 1315958753
   MS Data               1927683901 3852975932 1925292032
   MS Data               1953517373 3295311676 1341794304
   MS Data               1953519608 3242110960 1288591353
   MS Data               1953519615 3242110967 1288591353
MS Data               1927683901 3852975932 1925292032
   MS Data               1953517373 3295311676 1341794304
   MS Data               1953519608 3242110960 1288591353
   MS Data               1953519615 3242110967 1288591353
   MS Data               1953520030 3295316990 1341796961
   MS Data               1953520064 3295317024 1341796961
>  MS Data               1953523711 3907045374 1953521664

[ Continue ]
NTFS, blocksize=4096, 1000 GB / 931 GiB

7 Reply by mfleetwo

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Re: Partition Table Type MSDOS

The documentation for TestDisk (http://www.cgsecurity.org/wiki/TestDisk) or the forums (https://forum.cgsecurity.org/) would be the best place to find the information or help you need in using that tool.