Converting a dynamic disk to basic without data loss

Hello All,

Would really appreciate some help.

[FONT=verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif]I initially had 1 500gb dynamic disk, with one partition containing all my documents and windows files. I created a partition in the free space to copy my documents into so I could overwrite Windows keeping my documents intact. However I did not have enough free space for all my documents so after copying over one batch of files I shrunk the windows partition and extended my document partition. I had to repeat this again so I now have three extended document partitions.[/FONT]

I then put in the windows CD, formatted the OS Recovery, SYSTEM Reserved and Windows parititions but then was unable to install Windows as it did not recognise any disks. I attempted FixMBR etc but to no avail.

I searched around and saw i may be able to change the sector hex from 42 (dynamic) to 07 (basic), but im wondering whether doing so will preserve the extended partitions i have?

So my question is, will changing 42 to 07 preserve the extended partitions. Do I need to repeat for each 42 (like the link you posted) and then the three dynamic extended partitions will then become one basic partition?

At the moment I can not actually see the data so have no idea how to back it up? Otherwise I would do as you say and back it up, format and copy back over.

Sorry if that doesnt make any sense, hopefully these will help explain what i mean (the direct link to the gallery is here: ( ))


Acronis Disk Director (see documents spanned)

Active unDelete (again, three partitions)

HxD (showing 42)

So, basically im asking if i am safe to convert 42 to 07 WITHOUT losing any data?

Thank you for any help - i would really appreciate it


Last edited:


Excellent Member
Microsoft Community Contributor
Anytime you ask someone if your data will be safe while doing disk management scenarios, you are going to have a hard time getting an answer because no one can guarantee something will not go wrong. I am fairly sure Windows will not convert the drive, but possibly Acronis, which you seem to have.

So, without my making any type of judgments about the safety of your data, I will refer you to this Acronis page. Maybe going through it will help.

If you want to try to move the data prior to any operation, perhaps something like a live Linux bootable system would allow, but I do not know if Linux can read those types of disks.

And I suppose you saw this thread. Note the original poster does not appear to be a forum regular, and it was posted in March 2009--there may have been some changes since then.

I suppose the bottom line is if you cannot get your data in its current state and you do not have a backup, you will have to try...

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