At the time of this article's publishing there is not a way to set the Checked In status for participants to "No" in bulk on the RunSignup platform side. This is a problem for race series where participants may register for the whole series under a Super Event if bib assignment for each race in the series is Dynamic.

Fortunately, this can easily be fixed in RaceDay Scoring by following these steps:

Create a new Data Check

Go to Data Actions -> Data Checks -> New Data Check Report

Set a Participant Search Filter that will only give you the participants you want to alter

If the goal is only to un-check in the Series participants, set your Registered Event to be the Super Event's name. If it doesn't matter who is operated on, just leave these filters blank. In the below example, all participants in the 5K whose Checked In status is not (!=) "No" will be operated on.

Once the filter has been set properly, Search gives an output of everyone who meets the criteria.

Set the Data to Change 

This should be "Checked In" = "No" for this operation. 

Check All Participants

Verify that all the checkboxes on the right are now selected - this will apply to ALL participants, not just those on the current page.

Update Selected Participants

 Update Selected Participants should now be clicked.

 If you have a filter set to "Checked In" Is Not (!=) "No", the output should return nothing.

Now all participants operated in are "Un-Checked In".