Here are some steps I would try.
Install the latest version of Ethereum Wallet 0.8.8
Restart your computer to make sure that any old version of
geth you are running is terminated.
From https://github.com/ethereum/mist/releases, download
Ethereum-Wallet-macosx-0-8-8.dmg onto your hard disk. Navigate with Finder to your download directory and double-click on the downloaded file. You will see the following installation screen:
Drag the Ethereum logo icon on the top into the Applications icon. If you are asked whether you want to "Keep Both", "Stop" or "Replace", select "Replace".
From Launchpad, run the newly installed Ethereum Wallet application. Ethereum should download the latest version of
geth 1.5.5 and start running it.
If your Ethereum Wallet launches successfully, starts syncing and the the block number on the center top of Ethereum Wallet matches the "Last Block" block from https://etherscan.io/ then your blockchain is synced correctly.
Here is the block from the center top of Ethereum Wallet:
And here is the latest block from https://etherscan.io/:
If you are still having problems with syncing
Close Ethereum Wallet.
In your Terminal,
Iota:~ user$ cd $HOME/Library/Application\ Support/Ethereum\ Wallet/binaries/Geth/unpacked
Iota:unpacked user$ pwd
/Users/user/Library/Application Support/Ethereum Wallet/binaries/Geth/unpacked
Iota:unpacked user$ ls -al
drwxr-xr-x 6 bok staff 204 19 Dec 16:12 .
drwxr-xr-x 4 bok staff 136 25 Nov 11:26 ..
drwxr-xr-x 4 bok staff 136 1 Jan 1970 geth-darwin-amd64-1.5.3-978737f5
drwxr-xr-x 4 bok staff 136 1 Jan 1970 geth-darwin-amd64-1.5.5-ff07d548
Iota:unpacked user$ cd geth-darwin-amd64-1.5.5-ff07d548
Iota:geth-darwin-amd64-1.5.5-ff07d548 user$ ls -al
drwxr-xr-x 4 bok staff 136 1 Jan 1970 .
drwxr-xr-x 4 bok staff 136 21 Dec 23:55 ..
-rw-r--r-- 1 bok staff 32397 15 Dec 01:35 COPYING
-rwxr-xr-x 1 bok staff 29743692 15 Dec 01:37 geth
geth to remove your old blockchain data
Iota:geth-darwin-amd64-1.5.5-ff07d548 user$ ./geth removedb
Remove this database? [y/N] y
Now fast sync your blockchain data
Iota:geth-darwin-amd64-1.5.5-ff07d548 user$ ./geth --fast console
It should take several hours on a reasonably fast broadband connection to fast sync your blockchain data. After this you should be able to run Ethereum Wallet successfully.