What is the likely cause if the slapd daemon refuses to start after modifying indexes in slapd.conf and running slapindex?

The slapd daemon, which is part of the OpenLDAP server, may refuse to start due to various reasons after changes are made to the configuration or indexes. When considering the choice that you selected, running the init script as an ordinary user is a plausible explanation for the daemon's inability to start. The slapd daemon often requires elevated privileges to access certain system resources, read configurations, and manage related directories. If the init script is executed by a user without the necessary permissions, it may prevent slapd from starting correctly, as it cannot access required files or directories.

In this context, the operation of slapd relies heavily on permissions, and operating it as a regular user might lack the access necessary to initiate the service successfully. Consequently, elevating the execution to a user with the appropriate permissions (such as root) would usually resolve this issue and allow the slapd daemon to start as intended.

Understanding permissions in UNIX-like systems is essential, and ensuring that services are run with the correct user context is foundational for system administration tasks.