As background for editing custom user data, see:
When you set up a dynamic rule and activate it, the rule runs continually in the background. The rule relies on the custom user data linked to it. Safety Made Simple blocks certain changes to dynamic rule components, to keep the rules running.
The rule of thumb: you can add to a custom user data field, but you cannot remove from it.
While the rule is active, you can make the following changes to a custom user data field:
While it is linked to a dynamic rule, you cannot:
The following screenshot shows an example custom field called Driver's License, with new values being added in Comma separated values.

Note: After editing a custom data field, the dynamic rules need to synchronize the changes and apply the rules to all the relevant users. This step takes a few minutes. You cannot edit the rule while the rules are synchronizing.To make substantial changes to a custom user data field - removing data values, in particular - you need to:
The application returns to your group > Users.
Repeat these steps for each rule linked to the custom user data.
The following screenshot shows an example of the Driver's license custom user data field, as part of a dynamic rule, with the delete icon highlighted.

After removing all instances of the custom user data from the dynamic rules:
From main navigation, go to Settings > Users > Custom User Data to make changes to the custom user data field.
After finishing your changes to custom user data, you add the field back to the dynamic rules.