How to convert a dynamic disk to a basic disk without losing data

2011-08-22 cc-by-4.0 481 words 3 minutes

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Did you accidentally convert your basic disk to a dynamic disk? Have you looked for a solution but it costs money or you risk losing your data? Here is the solution.

This article has been imported & translated from my old french blog

This article has been imported from my old french blog which was hosted over http://rvmatysiak.free.fr/index.php/fr/tutgene/29-convertir-un-disque-dynamique-en-disque-de-base-sans-perte-de-donnees.html

What is a dynamic hard drive?

A dynamic hard drive allows you to create an unlimited number of primary and extended partitions, on several hard drives, and all this virtually. This allows you to exceed the limit of a basic hard drive which has a maximum of 4 partitions (under an MBR system).

Windows Disk Management overview of main dynamic drive — Disk Management overview

Practical

Preamble

We will need TestDisk. Download the latest stable version for your system. First, you will have to do everything to have only 4 active partitions. To do this, use your preferred partitioning utility. If you are on Windows you can use its manager partition which is accessible under Computer=> Right Click Manage=> Storage=> Disk Management. If you are on Unix/Linux you can use for example GParted.

Windows Disk Management overview of main drive — Disk Management overview

Put into practice

Warning

The example below is done on a Windows system.

Run testdisk_win.exe

Explorer windows over TestDisk folder from zip — TestDisk unziped folder

A console environment should appear:

Go to Create and enter.

Select the disk and Proceed

Then select your partition type.

Then Analysis.

You should see all partitions in dynamic/SFS. As you have noticed a partition has been added since then, this is the oem system recovery partition which is hidden.

Before making any changes, make a Backup.

TestDisk disk analysis view, selecting backup sub-action

Once you have done this, you should arrive on a similar console:

Here are the commands we will use:

 ↑ and ↓ to select partitions
 ← and → to change the characteristics of the partitions:
     * = Bootable partition
     P = Primary partition
     L = Logical partition
     E = Extended partition
     D = to delete the partition
     L = to load the backup if you made a mistake or are not sure.

In Windows 7, you have a partition named System which must be bootable.

TestDisk disk partition view with modification

Set up your partitions correctly. Once finished, type enter.

Check your settings for the last time.

If you made a mistake, quit the application. If everything looks good, apply the Write changes.

TestDisk disk partition view with modification, selecting Write sub-action — TestDisk disk partition view with modification, selecting `Write` sub-action

Confirm by typing y.

TestDisk confirmation view — TestDisk confirmation

And that’s it, you can exit the application “enter”.

TestDisk validating our changes and asking for reboot — TestDisk validating our changes

You must restart your computer for the changes to take effect. If you have done everything correctly, you should normally boot into your operating system.

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