Hi,
When I try to use the Add Roles and Features wizard to add Remote Desktop Services, it tells me that "the server has reboots pending and needs to be restarted".
Kindly confirm at which step or the specific roles you added that resulted in this error message.
If it is related to Role RDS gateway, kindly check the suggestion below: (quoted from Jemlay)
Check permission for C:\ProgramData\Microsoft\Crypto\RSA\Machinekeys\7a43*
https://social.technet.microsoft.com/Forums/lync/en-US/4cec7cde-eddb-475d-9c7a-7d81eb2f65c6/reboots-pending?forum=winserverTS
Moreover, please enable the RDMSDeploymentUI and RDMSUI-trace log to check if anything useful has been recorded during RDS installation.
https://support.microsoft.com/en-nz/help/2747656/introduction-to-log-files-that-are-useful-for-troubleshooting-rds-issu
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Thanks,
Jenny