I recently purchased a new Dell PC with Windows 10 home which I upgraded to Windows 10 Pro. Since there was an unused OEM license on the PC I thought I might try to use it by having a user remotely login simultaneously while someone was using the computer. The problem I found was that Win 10 only allowed 1 user at a time to be logged into the machine and logged the second user out.
After a bit of googling I found that a file could be modified to enable multiple users to logon to the machine simultaneously, though not the same user. This website http://woshub.com/how-to-allow-multiple-rdp-sessions-in-windows-10/ had information on installing RDP Wrapper or editing termsrv.dll to allow multiple simultaneous RDP connections. I liked the idea of modifying the .dll to avoid extra software installed. A problem was the hex for my version of Win10 2009 was not listed so I guessed from what was listed from previous versions. Search for the first part of the 12 nibbles that need replacing 39 81 3C 06 00 00 and replace all 12 with B8 00 01 00 00 89 81 38 06 00 00 90. The process I went through to do this is below.
Make a duplicate of the .dll so it can be replaced when needed
copy c:\Windows\System32\termsrv.dll termsrv.dll_backup
Make yourself an owner
takeown /F c:\Windows\System32\termsrv.dll /A
The result should be
SUCCESS: The file (or folder): c:\Windows\System32\termsrv.dll now owned by the administrators group
Give yourself full permissions
icacls c:\Windows\System32\termsrv.dll /grant Administrators:F
The result should be
processed file: c:\Windows\System32\termsrv.dll Successfully processed 1 files; Failed processing 0 files.
Stop RDP service
Net stop TermService
I downloaded a free hex editor from Windows store and found and replaced the hex in my 2009 version
39 81 3C 06 00 00 (I will update the 2009 version here)
B8 00 01 00 00 89 81 38 06 00 00 90
I restarted the computer and multiple simultaneous users can now logon. An issue is if Windows updates RDP and this will have to be done again.