MVC 5 Identity 2.0 lockout doesn't work

The line

UserManager.SetLockoutEnabled(user.Id, true);

is not locking or unlocking the account. This method is used to permanently enable or disable the locking out process for the given user account. As it stands, you are making a call that is basically setting this user account up to be bound by the rules of account locking. Making a call with the second parameter as false ie:

UserManager.SetLockoutEnabled(user.Id, false);

would allow you to setup a user account that is exempt from the rules of locking - this may be useful for an admin account.

Here is the code for UserManager.IsLockedOutAsync:

/// <summary>
///     Returns true if the user is locked out
/// </summary>
/// <param name="userId"></param>
/// <returns></returns>
public virtual async Task<bool> IsLockedOutAsync(TKey userId)
{
    ThrowIfDisposed();
    var store = GetUserLockoutStore();
    var user = await FindByIdAsync(userId).WithCurrentCulture();
    if (user == null)
    {
        throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture, Resources.UserIdNotFound,
            userId));
    }
    if (!await store.GetLockoutEnabledAsync(user).WithCurrentCulture())
    {
        return false;
    }
    var lockoutTime = await store.GetLockoutEndDateAsync(user).WithCurrentCulture();
    return lockoutTime >= DateTimeOffset.UtcNow;
}

As you can see, for a user to be classed as locked out, the lockout must be enabled as above and the user must have a LockoutEndDateUtc value that is greater than or equal to the current date.

So, to "permanently" lock an account, you could do the following:

using (var _db = new ApplicationDbContext())
{
    UserStore<DALApplicationUser> UserStore = new UserStore<DALApplicationUser>(_db);
    UserManager<DALApplicationUser> UserManager = new UserManager<DALApplicationUser>(UserStore);
    UserManager.UserLockoutEnabledByDefault = true;
    DALApplicationUser user = _userService.GetUserByProfileId(id);

    bool a = UserManager.IsLockedOut(user.Id);

    //user.LockoutEndDateUtc = DateTime.MaxValue; //.NET 4.5+
    user.LockoutEndDateUtc = new DateTime(9999, 12, 30);
    _db.SaveChanges();

    a = UserManager.IsLockedOut(user.Id);
}

The function SetLockoutEnabled doesn't lockout the user, it enables the lockout feature for the user

you need

UserManager.DefaultAccountLockoutTimeSpan = TimeSpan.FromHours(1); // lockout for 1 hour
UserManager.MaxFailedAccessAttemptsBeforeLockout = 5; // max fail attemps
await UserManager.AccessFailedAsync(user.Id); // Register failed access

It will record a failure, and lockout the user if Lockout is enabled and failure count is reached.

Set the shouldLockout value to true in your Login action (it's false by default)

            // To enable password failures to trigger account lockout, change to shouldLockout: true
            var result = await SignInManager.PasswordSignInAsync(vm.Email, vm.Password, vm.RememberMe, shouldLockout: true);