Welcome to the forum.
Can you post some screen shots?
"SW2017-18"? To my knowledge is either 2017 or 2018.
Are you in a drawing? In a drawing template?
I'm thinking there are no layers allowed in parts or assemblies, so if your layers toolbar is visible as part of your UI layout then it will be greyed for these docs.
Is there a dialog box open that waiting on you so another commands aren't permitted?
Can you perform any other commands? Or is it just layer that's not available?
Thank you so much for the hint! Problem solved! I was sketching in "part" when I sketched in drawing the Layer tab became visible.
Once again, thank you.
SW2017-18 could be the Edu license: (EDU 2017-2018)