You might find that if you have to kill Veeam.Backup.Service.exe manually then attempt to start the service, you receive:
“Veeam Backup Service started and then stopped. Some services stop automatically if they are not in use by other service or programs”
If you check the Event Viewer / Applications you’ll see this:
Service cannot be started. System.Net.Sockets.SocketException (0x80004005): Only one usage of each socket address (protocol/network address/port) is normally permitted at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress) at System.Net.Sockets.Socket.Bind(EndPoint localEP) at System.Net.Sockets.TcpListener.Start(Int32 backlog) at System.Runtime.Remoting.Channels.ExclusiveTcpListener.Start(Boolean exclusiveAddressUse) at System.Runtime.Remoting.Channels.Tcp.TcpServerChannel.StartListening(Object data) at System.Runtime.Remoting.Channels.Tcp.TcpServerChannel.SetupChannel() at System.Runtime.Remoting.Channels.Tcp.TcpServerChannel..ctor(IDictionary properties, IServerChannelSinkProvider sinkProvider, IAuthorizeRemotingConnection authorizeCallback) at Veeam.Common.Remoting.CSrvTcpChannelRegistration..ctor(String channelName, Int32 port, IDictionary channelProperties) at Veeam.Common.Remoting.CSrvTcpChannelRegistration.MakeWithAttempts(String channelName, Int32 port...
The clue for me was, “Only one usage of each socket address (protocol/network address/port) is normally permitted”
Something else is running and using protocol/network address/port that Veeam Backup Service needs. Just go back to Task Manager and kill Veeam Backup Manager, after which you’ll be able to start Veeam Backup Service.