Greetings Guardian! Here is every gold crate location as well as a trick to get the last crate in the Devil's Lair! And while the beta may be over, you'll be able to use this guide come September 9th, when the game officially releases.
The first crate is just up the stairs and through the first doors of the large building in The Divide in Old Russia.
The second crate is on the second floor of the room where you fight the first Wizard at the Lunar Complex in Old Russia.
The third crate is in the Forgotten Sea inside a small cave with water trickling down.
The next crate is also in Forgotten Sea along the rock edge just to the left of a small concrete platform.
The final crate is in The Devil's Lair. This is an event and you can't get back to it to explore and find the crate, you must open the crate during the even, so be sure to run down to the right and grab it just before or just after the final boss fight.