For mac users having wallet problems:
Firstly, before recommending a bunch of command line prompts that 8 out of 10 people have NO CLUE what they mean, let me explain it in simple terms so you don't delete something important!
1. Open your old wallet that contains your pre-sale address.
2. Click - File - Backup Wallet...
3. It will ask you to save your wallet file. I suggest saving it to several locations for safety (flash drive, desktop, etc.)
4. Your saved "wallet.dat" file is the ONLY THING unique to your wallet...(close your old wallet)
5. Right click on Finder - click - "Go to Folder" - type: ~/Library
6. Double click "Application Support" folder
7. Delete the entire "Archcoin" folder (this is your old wallet) MAKE SURE YOUR wallet.dat file is already backed-up
8. Now download the new wallet:
http://archcoin.co/wallets/archcoin-qt-osx.zip9. Open the new wallet, let it load, then CLOSE it (you'll see it has the wrong address)
10. Your new wallet replaced the folder you just deleted in Application Support
11. Repeat steps 5 and 6 and you'll see your new Archcoin folder in Application Support
12. Enter the Archcoin folder...delete the new "wallet.dat" file and replace it with your old one
13. Now reopen your new Archcoin wallet and it will contain your correct wallet address
For BTCarchitect giving the Syscoin guys such a hard time...his mac wallet launch wasn't a whole lot better.
Viacoin (with Drak) was the only IPO that I ever had a good experience.