BlockChain.Info Incorrect Balance Recently my Bitcoin-Qt client started crashing on start-up (running Mac OS X 10.7.4). I was able to stop the crashing by removing the blocks directory and letting it re-download the blockchain.

However, I don't really have time to re-download the forever bloating 13GB blockchain! So I tried importing my wallet.dat file into blockchain.info. Upon doing this, my total balance is now 1BTC short.

When I inspect the transactions, nowhere did I send 1BTC from that wallet. And when checking in Bitcoin-Qt, the coin is there and verified.  Unfortunately I can't dump the private key for this coin as I get an error in Bitcoin-Qt (I think due to my blockchain being out of date). As I was hoping to then import this key manually.

Is there anyway around this? Ideally I just want to get my balance into a wallet like Multibit, so I don't have to worry about the 13GB+ blockchain! Backup my wallet safely and know that my coin is secure and safe! In a crashing Bitcoin-Qt with a forever growing blockchain I don't feel too happy at the moment.

Currently available to me I just have my encrypted wallet, and it is currently imported to blockchain.info with the incorrect balance. Any suggestions? I feel like I tip toe around a lot with Bitcoin as I don't want to accidently delete anything I shouldn't!
As long as you keep your private/public keypair, you aren't in danger of actually losing the funds. 

The problem is most likely due to "missing inputs" for your current wallet. In order to spend bitcoins, your wallet must reference the inputs that gave your wallet the funds in the first place. The function of the blockchain is to keep track of these inputs from creation to their current wallet. Without the full blockchain, qt will not be able to reference inputs for spending, and thus won't show such inputs as existing in your wallet.

Download the blockchain. If you can't/won't sweep you private key into a new wallet that has access to the full blockchain. This will also serve to reset the oldest input in your new wallet.