Using a Bitcoin-Qt v0.16.0 ([downloaded from bitcoin page](https://bitcoin.org/bin/bitcoin-core-0.16.0/bitcoin-0.16.0-osx.dmg)) in an macOS High Sierra 10.13.4 

When I start after a fresh install Bitcoin-Qt as a mainnet node and wallet, the wallet prompt that about 203gb is going to be used in my disk
![image](https://user-images.githubusercontent.com/20187136/39899688-ba820bfe-5493-11e8-87d9-460ed5716a02.png)

When I start the node and wallet as testnet, shows the same message about the 203gb disk usage
![image](https://user-images.githubusercontent.com/20187136/39899756-17b31214-5494-11e8-8a57-60e604e74afb.png)

It seems that the second time the message is wrong, due that the testnet database uses about 14gb.
std::vector<unsigned char> base58Prefixes[MAX_BASE58_TYPES];
    std::string bech32_hrp;
    std::string strNetworkID;
    CBlock genesis;
    std::vector<SeedSpec6> vFixedSeeds;
    bool fDefaultConsistencyChecks;
    bool fRequireStandard;
    bool fMineBlocksOnDemand;
    CCheckpointData checkpointData;
    ChainTxData chainTxData;
    bool m_fallback_fee_enabled;
};
/**
 * Creates and returns a std::unique_ptr<CChainParams> of the chosen chain.
 * @returns a CChainParams* of the chosen chain.
 * @throws a std::runtime_error if the chain is not supported.
 */
std::unique_ptr<const CChainParams> CreateChainParams(const std::string& chain);
/**
 * Return the currently selected parameters. This won't change after app
 * startup, except for unit tests.
 */
const CChainParams &Params();
/**
 * Sets the params returned by Params() to those for the given BIP70 chain name.
 * @throws std::runtime_error when the chain is not supported.
 */
void SelectParams(const std::string& chain);
#endif