I have the same problem. This is all i get:
Launcher 1.0.8 (through bootstrap 4) started on osx...
System.getProperty('os.name') == 'Mac OS X'
System.getProperty('os.version') == '10.8.4'
System.getProperty('os.arch') == 'x86_64'
System.getProperty('java.version') == '1.6.0_51'
System.getProperty('java.vendor') == 'Apple Inc.'
Going to log in with legacy stored username & password...
Loaded 4 profile(s); selected 'Vanilla 1.6.1'
Trying to log in...
Logging in with username & password
Could not log in: Invalid credentials.
Delta time to compare resources: 436 ms
Download job 'Resources' skipped as there are no files to download
Job 'Resources' finished successfully
Afterwards, I tried logging in to mojang.com and it told me unknown e-mail or password. I then tried changing my password on mojang.com and afterwards on the launcher, but it still told me the same thing.
This happens for me as well on Mac OS X 10.8.4. When I close the launcher and open it again, only my most recently created profile can be logged in online. As well, once I close the launcher again, not even that one can be logged in online.