Opening an application to edit results in the error message: "_ undefined, maybe missing global qualifier"

Problem

When trying to edit a custom application, the following error message is displayed and/or appears in the localhost log:

  "_ undefined, maybe missing global qualifier"

When trying to open the application in Studio, it keeps loading.

1. Navigate to System Applications > Applications.

2. Click the edit button on the application.

   The system tries to open the application in Studio, which keeps loading.

3. Clicking on the application name.

   The system tries to open the application form to edit it, and the error message displays in that screen

Cause

A custom script include has the name '_' which conflicts with a base system script include with the same name.

Resolution

1. Search for script includes with the name '_' using the following URL:

   https://<instancename>.service-now.com/sys_script_include_list.do?sysparm_query=GOTOname%3D_

   This should result in two rows, one for application Studio and one for application Code Search.

2. Rename, delete, or deactivate any others.

   Confirm that this resolves the issue.