The system account and the account which installed the SCCM have the right of fully control the information of SCCM. When we use other account in the member of administrators group of the SCCM server, we may use "at" command to retrieval the user right.
 
Run the "Command Prompt" on the SCCM server, type"at time /interactive cmd.exe", run the SCCM console in the new "Command Prompt", then we can run the SCCM console with the system account, we can add another user account to SCCM.