When you open this database, you may see a security warning from Microsoft, that the database has been signed by an untrusted certificate. The certificate should show as 'USDA-ARS Jornada'. In order to prevent the security warning from displaying every time the database is opened, do the following procedure (you only have to do it once, per computer).

• When the 'Security Warning' alert shows, click the 'Options' button.
• The signature shows as 'USDA-ARS Jornada'. Click the 'Show Signature Details' link.
• Click the 'View Certificate' button.
• Click the 'Install Certificate...' button.
• In the Certificate Import Wizard, click 'Next'.
• On the 'Certificate Store' screen, leave the default ('Automatically') and click 'Next'.
• Click 'Finish'.
• When it asks 'Do you want to install this certificate?' answer 'Yes'. You should see 'The import was successful'.
• Click 'OK' to close the 'Certificate' screen.
• Click 'OK' to close the 'Digital Signature Details' screen.
• On the 'Security Alert' screen, click the 'Trust all documents from this publisher' option, then click 'OK'.

You may create/designate a specific folder on your computer as a 'Trusted Folder', and place the MDB file in that Folder (or a subfolder). See Access documentation on how to create a Trusted Folder.

Alternately, see:  https://office.microsoft.com/en-us/access/HA101980471033.ASPX

If you continue to experience problems, you will need to enable macros in Access. With Access open, click on the Access image in the top left corner then click the button at the bottom of the screen that reads Access Options. Click Trust Center in the left menu bar then click the Trust Center Settings button. Click Macro Settings in the left menu bar and select Enable all macros. Close and re-open Access.