Overwatch – Determining Which Team Starts on Offense in a Custom Overwatch Lobby

Really, the game only seems to care if you're on Attack or Defense. On KOTH maps, both teams are Attack.

The warnings I remember seeing are:

For both Attack and Defend:

• No Damage Dealers
• No Supports
• No Tanks
• Too Many Tanks
• Too Many Supports
• Too Many Of The Same Hero

The "Too Many" ones appear if there are 3 or more.

For Attack:

• Few Damage Dealers
  • If you only have one Offense.

For Defense:

• No Defense
• Few Defense
  • If you only have one Defense.
• No Builders
  • If you have no Torbjörn or Symmetra
• No Snipers
  • If you have no Widowmaker or Hanzo

Anyway, what this really boils down to...

• Attack
  • 2 Offense
  • 1 Tank
  • 1 Support
  • The rest filled as appropriate, but keep in mind the Too Many rules
• Defense
  • Widowmaker or Hanzo
  • Torbjörn or Symmetra
  • 1 more Defense if Symmetra is picked above.
  • 1 Tank
  • 1 Support
  • The rest filled as appropriate.

Torbjörn and Symmetra are the builders. They build turrets. This is what the warning message is referencing.