It means Valve has put you in the line to buy that Steam Machine bundle, but not everyone in the signup pool gets a guaranteed purchase right away. Based on the current reservation system, that message usually means your account was placed into the reservation queue and you should get a follow-up email if your slot comes up; otherwise you may be moved to the waitlist.

What the message implies

  • “Officially in the reservation queue” means you were selected in the randomized order, so a unit has been reserved for you in the purchase pipeline.
  • It is not the same as the console already shipping to you yet; Valve sends a later email when it is time to complete checkout.
  • If you do not complete the purchase in time, the reservation can pass to the next person in line.

Likely next step

  • Watch for an email telling you to finish the purchase.
  • Valve reportedly gives a limited window to check out after the notification arrives.
  • If you miss that window, your spot may be lost to the next buyer in the queue.

In plain English

Think of it like getting a numbered ticket at a crowded store: being “in the reservation queue” means you’re in line, but you still need your turn to actually pay and lock it in.

TL;DR

You’re not just “interested” anymore — you’re in line to buy the Steam Machine 512GB with Controller, pending Valve’s purchase email and checkout window.