Quick and dirty solution? Use their own initial hash.

how to To create a genesis block

Main.h

Delete Both Main Merkle & Genesis Merkle (example)
Main genesis block

static const uint256 hashGenesisBlock("0x000004611c87517dfd29fe7f34bd6da2e1ad3d305ac12afe80a3229069390f68");

To

static const uint256 hashGenesisBlock("");

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and inside Main.h too
Testnet Genesis

static const uint256 hashGenesisBlockTestNet("0x000004611c87517dfd29fe7f34bd6da2e1ad3d305ac12afe80a3229069390f68");

To

static const uint256 hashGenesisBlockTestNet("");

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inside Main.cpp Change this to your Timestamp wanted
(Example)

const char* pszTimestamp = "Blockchain.info Block #312427 2014-07-25 14:15:16";

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inside: Main.cpp
Change these both to your Epoch Time wanted //Unixtime check google

txNew.nTime = 1406297716;  (example) (example) 
block.nTime    = 1406297716;  (example) (example) (example)

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inside: Main.cpp Change these to 0

block.nNonce   = !fTestNet ? 190271 : 190271;   (example) (example) (example)

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inside: Main.cpp Change this to say true

if (false && (block.GetHash() != hashGenesisBlock))

into

if (true && (block.GetHash() != hashGenesisBlock))

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inside: Main.cpp Delete the Merkle root

assert(block.hashMerkleRoot == uint256("0xc9c8f6250a60dc79038b9ae68ff747488ac80d4a2db0b194cf49628495448d21"));

To

assert(block.hashMerkleRoot == uint256(""));

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Now Compile the Wallet, and let it crash. as next you find on the debug file the Merkle Root/Hash replace it into the blank space from you step before. but make sure that you have to add to the beginning 0x just compare and undo the steps with the new infos.

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Save the Main.cpp with the New hashMerkleRoot added by you. and recompile. then start again and let the wallet crash one more time like before. visit again the debug log and replace other infos.

you find in the debug block.nNonce you remind that you remove that before. and the Genesis/Block Hash .. you remind you delete this as first. copy and paste into the free space inside the Main.h and add 0x on the beginning too.

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That's it. Save all files and compile one more time. and you are a Coin Developer :-)

You can get original blockchain (curracy that you fork) and read genesis block. Then you can see what happens there and maybe you will find bug in the code faster.