To check if your desktop wallet is on the correct blockchain and not on a minority fork, please compare the block height (current number of blocks) of your wallet with the block height of the explorer.
To make sure that you are on the right block and is on the right network, please perform the following check: From the debug console (Tools -> Debug Console), type: getinfo. Note the block number. That is the block number that your wallet is currently synced up to. Now type: getblockhash xxxxxx (replace xxxxxx with the block number from getinfo above) Compare the hash to the block explorer’s block hash for that same block via the Blockchain Explorer by pasting the block number into the search box. If the hash is different, you are not on the right chain and you should update to the latest wallet release (if not already on it), restart the wallet, wait until the wallet is fully synced, and check steps 1 to 4 again. If the wallet still not matching the block explorer, please resync the blockchain. If the hash matched up between your wallet and the block explorer, then your wallet is on the right network. If your recipient still hasn’t received your coins, you need to ensure that the recipient is also on the right network and synced up to the latest block with no delays.