After modifying the indexes for a database in slapd.conf - and running slapindex - the slapd daemon refuses to start when its init script is called. What is the most likely cause of this?

Index compatibility is typically handled by `slapd` itself, not an 'init script' specifically, and indexes generally conform to the database backend.

There is no standard `slapsign` utility or requirement to 'sign' indexes for `slapd` to start; this concept is not part of OpenLDAP indexing.

While invalid indexes can cause `slapd` startup issues, the `slapindex` command itself usually reports errors if indexes are fundamentally invalid or malformed during its execution, making a silent failure from the init script less likely than a permissions issue.

When `slapindex` is executed, often by a root user, it creates or modifies index files within the OpenLDAP database directory; if these new files are owned by root and lack read/write permissions for the `slapd` daemon's operating user (e.g., `ldap`), the daemon will fail to start due to insufficient permissions to access its own database.