after update on 6.18 , winbox refuse to work....

RouterOS Beginner Basics
1

pls

2

Which winbox are you using ?
v2 or v3 beta ?

3

I noticed the same with v3 beta winbox (the one available from the downloads section)

(Groove with 6.18)

Just had to download an older version of winbox

4

There are still problems in the beta version.
Try the stable one and it should work. You can download it from your board. When you open the ip address of your routerboard with a web browser there is a download link for winbox.exe