Linked below is the most recent US Customs’ guidance on recordkeeping in ACE.
In sum, CBP will not request an entry filer to produce the data (formerly contained in CBP Forms 7501, 3461, 214 or 7512) that the filer previously transmitted to and was retained by CBP unless the agency has the need for these records. In that instance, the filer may re-transmit or otherwise provide the data electronically or reproduce the entry/entry summary data using an ACE report.
This policy does not affect other recordkeeping requirements, such as the need for the filer to maintain supporting documentation used to create the data transmitted to CBP, or the need to maintain original documents.
Click the link to see the complete CBP recordkeeping policy dated January 2016. RECORDKEEPING IN ACE FINAL 1-28-2016