I can start the service correctly if the service's "Log on" account has a password. But when I remove the user password and try again, I got the error: "Error 1069: The service did not start due to a logon failure"
Can't a service runs under an account with empty password?
What version of Windowss? I believe under Windows XP at least, a service can't be run as a user with a blank password.
If you've time spare, you could try setting things like "allow interaction with desktop" on the service, and "allow log on a service" for the user.
But I think you'd be better with a password, for several reasons. Why don't you want one?
By default all modern versions of Windows have a Local Security policy that restricts users with blank passwords to logging on at the local console only. In other words, a user with a blank password must physically be at the computer in order to log on. The user cannot log on as a service, as a batch user, over a network, etc.
This can be changed by changing the policy under Local Policies -> Security Options. Or by changing the LimitBlankPasswordUse value under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa to zero.
But, and this is very important, this will set up a serious hole in your security since users with blank passwords will now be able to log on remotely and blank passwords are pretty easy to guess. I can't think of any reason to have a service run under an account with no password, so my recommendation would be - don't do it.