A ferramenta de Recuperação de Senha de Rede NirSoft funcionou para mim, parece que o Windows agora salva as senhas da Área de Trabalho Remota com as outras senhas de rede. A partir da descrição da ferramenta:
When you connect to a network share on your LAN or to your .NET Passport account, Windows allows you to save your password in order to use it in each time that you connect the remote server. This utility recovers all network passwords stored on your system for the current logged-on user. It can also recover the passwords stored in Credentials file of external drive, as long as you know the last log-on password.
Certifique-se de pegar a versão x64 se estiver executando em 64 bits.