Dynamic drive converting to NTFS without data loss.
You only need a dynamic drive if you want to have more than 3 partitions.
Actually 4
If you already have 4 partitions with NTFS, an external drive will not be assigned a drive letter.
This has to be adjusted with disk management.
If you need fewer partitees, a dynamic drive is not necessary.

Converting from Dynamic to NTFS can be done with Diskpart, but that is not without risk.
Before you know it, you have lost everything.
The working method is as follows:
Clone the original hard disk.
Place the clone in a dock station on a computer with the AOMEI program.
AOMEI Dynamic Disk Manager Pro is actually the only (paid) program that works.
Follow the instructions.
If it is successful and all the data is still present, then this NTFS disk can be cloned to that original dynamic disk.

It is recommended to use a 1 XP machine.
Especially when transferring files from a Win 7-8 or 10 drive, you don't have any problems with the assigned privileges that you must give to "everyone" to get access and copy the files.
XP has no problem whatsoever with this. 
Folders can be read and copied directly without unpleasant rights management

Click on photo to enlarge