Troubleshoot scenarios and solves

Match the message

Increasing runtime helps search only after a valid schedule can be constructed. It does not fix invalid references or insufficient capacity.

Fix Scenario needs changes

Browser preflight checks three groups of problems:

• People and groups: blank or duplicate records;
• References: rules, attendance, group overrides, attributes, or solver scope referring to removed people, groups, attributes, or sessions;
• Capacity: fewer usable places than attendees in a session.

The notification shows the first problem and Plus N more issues when applicable.

Capacity

Open Groups and the reported session. Compare attendee count with the sum of session capacities. Increase a real capacity, add a group, reopen a group whose session capacity is 0, or correct participant Session Participation.

References

Open the section named by the action. Re-select current people, groups, attributes, or sessions, or delete the obsolete row. This commonly occurs after replacing a participant list or reducing the session count.

Conflicting requirements

The solver may report conflicts such as:

• more Fixed Placements than a group can hold;
• Fixed Placements that contradict Keep Together;
• the same people covered by both Keep Together and Keep Apart in the same sessions;
• group minimum occupancies that cannot all be reached.

Correct the people, groups, session scope, or capacity so the requirements can hold at once.

Investigate a preference violation

A nonzero Avoid Repeats cost or a Prefer Together, Prefer Apart, Balance Attributes, Attribute Totals, Encounters, or Group Visits deviation is not a runtime failure.

For Avoid Repeats, inspect Repetition Penalty in Score Breakdown and select costly pairs in the Pair Meeting Matrix. For a scoped preference, expand Constraint Compliance, the relevant family, and the individual card. Check:

1. the measured people, groups, and sessions;
2. the actual value and target;
3. attendance and capacity in those sessions;
4. other preferences or objectives that compete with it.

Change the scope or target when it describes the wrong measurement. Change weight or penalty function when the target is correct but has the wrong relative priority.

Fix runtime startup or catalog errors

For repeated worker, WebAssembly, or Available Solvers errors:

1. reload the page once;
2. use a current Chrome, Edge, Firefox, or Safari release;
3. disable script blockers or network filters for GroupMixer;
4. open the normal site instead of a restricted iframe;
5. reduce Parallel lanes to 1 if the browser is short on memory.

If the error returns, open Advanced error details. Select Copy technical details to copy the full text. Select Send problem report when available.

Handle budget, infeasibility, and starting-point errors

A run that reaches its time budget with a valid result completed normally with its best saved incumbent. Review that result. If no valid candidate was constructed, the message states that feasibility was not established within the budget.

Check requirements, capacities, and Scope before increasing Effort.

A missing or stale saved Starting Point stops the run. Select an available result from the current scenario or switch Starting Point to default construction. If GroupMixer reports that a warm start was adjusted, review its retained, repaired, filled, and dropped assignment counts before relying on continuity.

Recover results and workspace data

Result not found means that result ID is unavailable for the current saved scenario. Saved result URLs refer to browser-local data and are not portable share links.

Workspace failures use titles such as Unable to load workspace, Unable to migrate saved setup, Unable to create workspace, or Unable to save this example. Before clearing site data:

1. export any scenario or result still accessible;
2. reload once;
3. allow site storage and leave private-browsing mode if it blocks persistence;
4. check available device storage.

Report an incorrect result

Send a problem report when a returned schedule:

• violates Fixed Placements, Keep Together, or Keep Apart;
• assigns a person twice in one session or outside their Session Participation;
• exceeds an enforced group capacity;
• disagrees with the saved scenario snapshot.

The Send problem report dialog prepares anonymous technical context. The displayed full error text and participant names are not sent. Attaching anonymized scenario structure is optional.

If you separately paste technical details into a public issue, remove participant names and sensitive scenario content first.