If Uncheck Power is countered by Wind Wall, are units exhausted?

Ruling: Uncheck Power exhausts friendly units as part of spell resolution, not as a cost. If the spell is countered by Wind Wall, your units are not exhausted and remain in their previous state.

Sequence:

• Uncheck Power is played and put on the stack
• If countered by Wind Wall, the spell does not resolve
• Units are not exhausted because exhausting happens at resolution, not when playing the spell

Nuances:

• The exhausting effect is part of resolution, not an additional cost paid when playing the spell