solve log · 12 dated events since 2017, 8 of them change a game · newest: Late Aug 2026
McKinsey does not announce changes to Solve, and forum posts and prep pages keep describing games that are gone. Here is every change we can date, how sure we are of each, and what we changed in DrillCase because of it.
The game-based assessment was piloted with about 500 London-office candidates in late 2017.
Solve was built with the start-up Imbellus. McKinsey runs its own Game-Based Innovation Lab, which has built games since 2020.
Plant Defense was replaced by Redrock Study around March 2023.
Redrock Study ends with a Cases part of 6 short mini-cases (it had 10 when Redrock launched in 2023).
Sea Wolf asks you to pick microbes to clean up 3 contaminated sites in 30 minutes.
Most recent reports say Ecosystem is no longer part of the standard Solve. When it left is disputed.
A 65-minute invitation reportedly means Redrock Study (35 min) + Sea Wolf (30 min).
McKinsey’s blog says Solve is “used to evaluate analytical thinking in over 300,000 candidates annually”.
McKinsey’s FAQ: “The length of your Solve assessment is outlined in your invitation email.”
McKinsey’s FAQ: “Each task within Solve will begin with an untimed tutorial.”
McKinsey’s FAQ says that, except as a disability accommodation McKinsey has approved in writing, you may not “use applications, websites, AI tools, or pre-prepared notes” or “record or capture screenshots of any part of the assessment”, and that you take it “alone, without assistance from others”.
The Sustainable Futures Lab most candidates report runs 20 minutes: one ranking task, then 12 multiple-choice situations.
An 85-minute invitation reportedly means Redrock Study (35 min) + Sea Wolf (30 min) + Sustainable Futures Lab (20 min).
Some 95-minute invitations reportedly carry a rebuilt SFL of about 30 minutes: a three-day simulation managing four researchers. McKinsey has published nothing about it.
A 95-minute invitation reportedly means Redrock Study (35 min) + Sea Wolf (30 min) + Sustainable Futures Lab (about 30 min).
The log, newest first
Each date is the earliest credible report, not an announcement. Where sources disagree, both readings are shown. Every source shows the day we last read it; we aim to re-read each one every 30 days.
Caveat: Early reports, possibly a limited test; two coaches read it as the 85-minute test plus a buffer.
DrillCaseNot built. There is no reliable description of the rebuilt SFL yet, so DrillCase does not claim to simulate it.
Caveat: March 2026 in some sources, “start of 2026” in others. McKinsey has published nothing about SFL.
DrillCaseDrillCase’s Sustainable Futures Lab practice uses this 20-minute format: rank four opening moves, then respond to twelve situations.
DrillCaseDrillCase keeps the clock stopped during its tutorials and teaches only methods you can run by hand. It does not build solvers or cheat sheets for the live test.
Caveat: The phase-out is dated anywhere from 2024 to early 2026; rare 110-minute invitations may still include Ecosystem.
DrillCaseDrillCase keeps Ecosystem practice for anyone whose invitation still names it. It is labelled as no longer in the standard test, and the study plan marks it optional.
Caveat: A coach in the same forum thread says no one knows for certain whether it counts. Total time is reported as 110 minutes by a candidate and 100 minutes by MConsultingPrep. Prepmatter says Sea Wolf ran 35 minutes before July 2025.
DrillCaseDrillCase’s Sea Wolf practice follows this format: three sites, one 30-minute clock.
Caveat: Prepmatter lists the cut among the changes it links to the July 2025 rollout, without a date for the cut itself.
DrillCaseEvery DrillCase Redrock study ends with 6 mini-cases (counted 30 Sep 2026).
Caveat: Redrock was reportedly seen in testing during 2022.
DrillCaseRedrock Study is DrillCase’s main Solve practice task, always on the clock.
Caveat: McKinsey’s blog words it as the lab forming “after acquiring Imbellus”.
Stale advice detector
A page's “updated” date does not mean its content is current. Check the claim, not the date.
No longer true: Solve is two games: Ecosystem and Plant Defense.
Plant Defense was replaced by Redrock Study. Most invitations today are Redrock and Sea Wolf.
Sources: Mar 2023 in the logNo longer true: Redrock ends with 10 mini-cases.
A forum coach reported 6 in March 2024, and prep sites now describe 6.
Sources: By Mar 2024 in the logNo longer true: The ocean game is an unscored beta you can skip preparing for.
Sea Wolf is on every sitting and reported to count: 3 sites in 30 minutes.
Sources: Jan 2025 in the logNo longer true: Expect Ecosystem and Redrock, about 70 minutes.
The usual invitation is 65 minutes: Redrock (35) and Sea Wolf (30). Ecosystem is reported only in rare 110-minute invitations.
Sources: Mid-2025 in the logNo longer true: Every Solve invitation is 65 minutes: Redrock and Sea Wolf.
Still the most common length, but an 85-minute invitation reportedly adds a third game, the Sustainable Futures Lab (20 minutes).
Sources: Early 2026 in the logNo longer true: The Sustainable Futures Lab is always 20 minutes.
Still the most-reported version. Some 95-minute invitations may carry a longer, rebuilt SFL; this is not settled.
Sources: Late Aug 2026 in the logWhat McKinsey writes down
McKinsey’s FAQ says that, except as a disability accommodation McKinsey has approved in writing, you may not “use applications, websites, AI tools, or pre-prepared notes” or “record or capture screenshots of any part of the assessment”, and that you take it “alone, without assistance from others”.
McKinsey’s FAQ says that, except as a disability accommodation McKinsey has approved in writing, you may not “use applications, websites, AI tools, or pre-prepared notes” or “record or capture screenshots of any part of the assessment”, and that you take it “alone, without assistance from others”.
So DrillCase teaches methods you can run by hand and never builds a solver. How we teach
DrillCase is an independent practice provider. It is not affiliated with, endorsed by or sponsored by McKinsey & Company, Boston Consulting Group or Bain & Company.