This article introduces how to limit the User selection field to hold only one value.
By default, User selection fields in Kintone can hold information of multiple users. The number of users that can be selected for the value cannot be controlled with Kintone's built-in features.
The only field needed for this customization to run is the User selection field.
Prepare the App
Create an App with the following fields and settings.
|The person in charge
Navigate to the Record Create page, Record Edit page or the Record List page. Add 2 or more users to the User selection field and click on Save. The record should be unsaved, and an error message should appear.