You Cannot use contains for objects they are not strings
contains only is meaningful when you have a partial case Sensitive pattern
here is how you may use contains
0: kd> dx Debugger.Sessions.First().Processes.Where(p=>p.Name.Contains("Taskm"))
Debugger.Sessions.First().Processes.Where(p=>p.Name.Contains("Taskm"))
[0x2c14] : Taskmgr.exe
or if you have a proper complete case sensitive pattern you can simply use == on the Process name
0: kd> dx Debugger.Sessions.First().Processes.Where(p=>p.Name == "Taskmgr.exe")
Debugger.Sessions.First().Processes.Where(p=>p.Name == "Taskmgr.exe")
[0x2c14] : Taskmgr.exe
0: kd> dx Debugger.Sessions.First().Processes.Where(p=>p.Name == "tAskmgr.exe")
Debugger.Sessions.First().Processes.Where(p=>p.Name == "tAskmgr.exe")
0: kd>