User scenario
My original operating system was Windows 7 Professional or Enterprise. Now I have a
new Windows 10 Enterprise desktop. I put these hard drives from my original PC to my
Windows 10 and want to retrieve data. The original system hard drive was fine, and
the other shows dynamic disk invalid. The only option provided in Windows 10 was
Convert to Basic Disk, but the option will lose all the data. What should I do to
save my data?

Real cause to invalid dynamic disk
When your Windows operating system stating the dynamic disk as invalid, you would be
in panic and want to know why it happened. There are so many reason could account
for invalid dynamic disk error, like bad sectors, hard drive issues, bad SATA cable,
virus attack, or malware. And the most important reason could be the Windows
incompatibility issue.
Solutions
The below text will show you several ways to repair invalid dynamic disk. According
to the real cause of invalid dynamic disk, we list 4 effective ways to fix.
Upgrade your Windows OS version
As we all known, dynamic disks are not supported in all version of Windows operating
system, If the dynamic disk shows as invalid, you could upgrade to another Windows
OS that supports dynamic disks. Then the problem should be fixed.
Reactivate the invalid dynamic disk with DiskPart
How to repair invalid dynamic disk without data loss using CMD in Windows 7/8/10? The
instruction will lead you to the right way.
Input cmd in search box and choose Run as
Administrator.
Type diskpart and hit enter.
Type list disk (Missing disks are numbered M0, M1, M2, and
so on; and offline disks are numbered 0, 1, 2, and so on.)
Type select disk. (The disknumber is the
number of invalid dynamic disk you want to bring online.)
Type online disk

If this solution is not working for you, try the next one.
Convert dynamic to basic disk via Disk Management
Type diskmgmt.msc in search box on the desktop to enter Disk
Management.
Right click the invalid dynamic disk and choose Convert to Basic
Disk.
If the option Convert to Basic Disk is greyed out, you have to delete all partition and data on it
(you will lost all of data) and then select the option to convert to basic disk to
repair invalid dynamic disk issue.
Try another reliable way to repair invalid dynamic disk without data loss – AOMEI Partition Assistant Professional, if you do not have the plan to lose your data.
Convert dynamic to basic disk without data loss via AOMEI Partition Assistant Professional
AOMEI Partition Assistant Professional is a powerful dynamic or basic disks and volumes management
software for Windows 10/.1/8/7/Vista/XP/2000 and if you are using Windows Server
2003/2008/2011/2012/2016 you can use Server Edition.
It allows you to convert disk between basic and dynamic
without losing data. And allows you to manage dynamic disks and volumes, like extend, shrink, create, delete dynamic volumes, create volume wizard, move volume slice wizard, and add drive to RAID, etc.
Before converting, backup all the data on dynamic disk in case you have to
recover data. Here are the detailed steps to convert:
1. Install and run AOMEI Partition Assistant Professional; click Launch AOMEI Dynamic Disk Manager button to lauch it.

2. Then right click the invalid dynamic disk & choose Convert to Basic Disk.A prompt window will show up, and hit OK.


3. View the changes of the invalid dynamic disk, and press Commit.

4. At the Pending Operations window, press Proceed button to repair invalid dynamic disk without losing data in Windows 7/8/10.
The operation requires a reboot to take effect the conversion.
Now, the dynamic disk shows as invalid problem should be repaired and it will never
bother you again.