You can specify a full path to a file or a directory, such as ocsp.trust.store=C:\Program Files\Nexus\OCSP Responder\certs\trust.store
.
Alternatively, specify a relative path (default): ocsp.trust.store=certs/trust.store
("/" makes the specification OS-independent)
On both Windows and Linux environments, the relative path will start from the <configuration root> directory.