How to Reset a Trial Vault and Farm It Repeatedly

Open the Vault First

You can only reset a trial vault after it has been opened and its loot claimed. Walk up to the vault and interact with it using a trial key as normal. Once the loot pops out and the vault goes dark (its opened state), you are ready to reset it.

Use a Second Key to Reset

With the vault in its opened state, take another trial key in your hand. Use that key directly on the same vault block. The vault will flip back to its unopened state, and you can immediately interact with it again to claim a fresh roll of loot. The key is consumed in the process, just like a normal vault opening.

Keep the Loop Going

Each reset costs one key, so the cycle is: open vault, collect loot, use another key to reset, open again. Stockpile trial keys before you start farming so you are not running back and forth. Ominous trial keys work the same way for ominous vaults, and the reset preserves the vault's type, so you do not lose the ominous variant by resetting it.

If a key does nothing when you use it, check that the vault is actually in its opened state. Using a key on an unopened vault just opens it normally instead of resetting.