You can write script at event handler BeforeStart at Managed Application Module, and function at Common module, which check another connections with same user
Code
//Managed Application Module
Procedure BeforeStart(Cancel)
If CommonFunctions.IsAnotherUser() Then
Message = "The same user already open 1c. Current connection exit.";
TextMessage = New TextDocument;
TextMessage.SetText("
|<HT ML><HEAD>
|<MET A content=""text/html; charset=utf-8"" http-equiv=Content-Type>
|<MET A name=GENERATOR content=""MSHTML 9.00.8112.16464""></HEAD>
|<BODY><h2>" + StrReplace(Message, Chars.LF, "<br>") + "</h2></BODY></HTML>");
FilePath = GetTempFileName("html");
TextMessage.Write(FilePath);
#If WebClient Then
DoMessageBox(Message, 3);
#Else
RunApp(FilePath);
#EndIf
Cancel = True;
EndIf;
EndProcedure
// Common module "CommonFunctions"
Function IsAnotherUser() Export
CurrentConnectionNumber = InfoBaseConnectionNumber();
UserUUID = InfoBaseUsers.CurrentUser().UUID;
ConnectionArray = GetInfoBaseConnections();
For each CurConnection In ConnectionArray Do
If (Find(CurConnection.ApplicationName, "1CV8") > 0) AND (NOT CurConnection.ConnectionNumber = CurrentConnectionNumber)
AND (NOT CurConnection.User = Undefined)
AND (CurConnection.User.UUID = UserUUID) Then
Return True;
EndIf;
EndDo;
Return False;
EndFunction // CheckAnotherUser()
