English to Russian Law/Patents Law: Contract(s) NDA

Добрый день!
Помогите, пожалуйста, перевести "but prior to" в следующем контексте:

Notwithstanding the immediately preceding sentence, the Receiving Party is not obligated to return or destroy (a) any Proprietary Information stored on back-up media for purposes of disaster recovery in the ordinary course of business that may be subject to destruction in due course, provided that the Receiving Party is precluded from accessing such Proprietary Information after expiration or termination but prior to its destruction, and (b) residual or latent data such as resulting from deleted files, automatically created temporary files, printer spool files, and metadata that can only be retrieved by computer forensics experts and is generally considered inaccessible without the use of specialized tools and techniques.