Is there any chance to use the mac app on leopard ?
please try to install this version and see if it works: http://files.wedoist.com/dbb88e0cacd358c4bb31da36b438475a/as/TodoistApp.zip
This doesn't work for me -- I can't log in with my Google account. It just opens a Google login window in Chrome and nothing happens in the app. Please don't make me upgrade my entire OS to use your desktop app... I'd probably rather find another to-do app that _does_ work right in OS X 10.6. Which is a shame. I would be willing to pay for Todoist if I could get this to work.
Unfortunately, the old version of the app is no longer supported by us and there may be some issues with the Google login process.
You could try to go to the web-app at http://todoist.com click on the gear icon in the top-right corner to go to Settings -> Account and set a password for your Todoist account. Then, you should be able to log in by typing your GMail address and password combination manually.