When launching target instances Windows Server may boot with all the disks as read only.
This a common issue that occurs when detaching and attaching data disks. This issue can be resolved using steps in the following Microsoft TechNet article.
To simply this step, you can also leverage the attached CloudEndure post launch script which automated this process.
Note that this script will just clear the readonly flag, and won't bring the disks online. If you want it to ensure all disks are brought online as well, delete the REM from the following line:
ECHO REM online disk>>offreadonlyfile.txt
For more information on post launch scripts, please refer to this FAQ.