If you are trying to monitor a non-domain machine on a workstation, you may run into an issue where you get access is denied, even if you are using the credentials for a local administrator.
In this case, you may need to add a registry key that allows the account to access the ADMIN$ share.
Open "RegEdit" and navigate to:
Create a new DWORD value named "LocalAccountTokenFilterPolicy" and set its value to 1
Once you reboot the machine, you should be able to manage it from the management console.