Strange number appears when booting and then log in.

[leonwulf]

There's a strange number appears after booting my mac and when i want to log in and fill in the username and password

It happens like this:

My Macbook (2)* 😕
Username: ...
Password: ...

My Macbook (3)* 😕 😕
Username: ...
Password: ...

*Those happened several times ago

and NOW

My Macbook (4) 😱 😱 😱
Username: ...
Password: ...

I really have no idea, what was all about. Can anybody help me and explain about it..?! 🙁🙁🙁

Thanks

 

[Eidorian]

How many other computers are on your network? Do you have a router?

 

[leonwulf]

How many other computers are on your network? Do you have a router?

Yes, I have a router. There are 5 other computers on my network.
Is that taking any effect??

 

[Eidorian]

Yes, I have a router. There are 5 other computers on my network.
Is that taking any effect??

Are they all Macbooks? Do you have access to the router and information on its assigned addresses/DHCP?