Is there a way to convert dynamic disk to basic without data loss ?  

Hi empleat,
This is what I did to get my files off a dynamic disk and convert it back to a Basic Disk. I don't come to this forum but I'm just offering what I did just to help you, or others.

I have been using an old computer with Windows XP as a basic file storage unit. My primary drive is an 80Gig IDE and the secondary drive is a 1Gig Sata drive. I booted it up a few days a ago and Windows XP would not fully load. So before busting out my Windows floppy boot disk to see if I can get to the secondary drive and copy about 13,000 files off of it I decided to go a little more modern. Off Amazon, i purchased an adapter that will plug into an IDE or Sata drive on one end and has USB on the other end. Thanks to the adapter, I plugged the IDE drive (with the corrupt Windows XP) into a laptop which has windows 10 and was able to read and copy all the content just as if I plugged in a normal USB flash drive. I then plugged in the Sata drive and although my laptop detected the drive it was not able to read it. I ran Windows Disk Manager and it turns out the drive was marked as a Dynamic - invalid disk.
I downloaded the software tools mentioned by the others and ran them as the demo version. Before anyone of them would allow me to either change the drive from Dynamic to Basic or extract the files I had to pay for it, which is fair considering they put the work to develop and maintain that software. However, I did a bit more searching and came across Testdisk software (TestDisk - CGSecurity) which is all free. The user interface resembles DOS, no windows style GUI. There is a PDF file within the download that contains instructions but i have to admit that they aren't the greatest. I ran the software (the exe file) and it found my drive and the folder/files on the drive as well. My approach was two fold - first copy everything then secondly see if i can change the disk from dynamic to basic. First I copied each folder off the drive onto my laptop. You can select one or multiple at a time. Once I copied them off the drive my next step was to convert the drive from Dynamic to Basic. This second step wasn't really necessary since I got my files but I wanted to try it anyways. Testdisk calls it Primary Bootable (the symbol was *P). I changed it successfully. I reconnected the drive to my Windows 10 laptop via the adapter and I could now read and copy the entire Sata hard drive just like it was a USB flash drive. I ran Windows Disk Manager and it is listed as a Healthy Disk.

So I needed the USB to hard drive adapter + the Testdisk freeware to both copy files and change the drive from Dynamic to Basic.

I know this is an old thread but I'd like to share with many of you that through a lot of researching and trial and error, I have found a way to overcome this issue. I recently had a server that I foolishly converted to "dynamic disk" and when upgrading my 750 GB drive to a 2 TB, I found out that I was stuck on the same 750 GB partition and was unable to expand it due to it being "dynamic". The trick that saved me was knowing how Microsoft's imaging works. By using DISM, you can actually capture an image from the drive that you want to convert and apply it to a new drive or even the same drive that you're currently using, all without data loss. If you'd like me to write up a tutorial on how to do this, simply let me know and I'd be happy to share. So far, I have not found any other way to do it other than the way I have done it, unless you're willing to pay for expensive software. I'm not discounting software manufacturers, it's just that sometimes, they don't always fulfil our needs.