After an administrator added comments to each line of the ACLs in slapd.conf, the ACLs ceased to function properly. What is the most likely cause of this?

In OpenLDAP `slapd.conf` files, particularly in older versions, ACL blocks enforce a strict syntax. Placing comments directly within an ACL rule, or even on a separate line but inside a multi-line rule definition, can cause parsing errors and prevent the entire ACL from being applied correctly.

The pound (`#`) character is the correct way to denote comments in `slapd.conf`; the issue is typically *where* comments are placed, not the character used.

Comments can be used in `slapd.conf` on their own lines using the `#` character; the problem arises when they interfere with the strict syntax of certain configuration blocks like ACLs.

The pound (`#`) character is the correct comment character in `slapd.conf`; if comments were added, it is assumed the correct character was used, making the placement the issue.