If the Time Out app doesn't start properly when you launch it, or shows up in the Dock as not responding, the data might be damaged.

Firstly, try to restart your Mac. That might solve a temporary issue.

If that doesn't help, try this:

1. Quit or Force Quit Time Out if it's running.
2. Go to the Finder, and choose the Go ▶ Go to Folder... command.
3. Paste in this path, and click Go:
   ~/Library/Group Containers/6Z7QW53WB6.com.dejal.timeout.free
   (If you have the direct edition from this website, remove the ".free" on the end.)
4. Drag the revealed folder to the Desktop.
5. Re-launch Time Out; that'll use fresh data.

You'll need to reconfigure your breaks and other settings. You could drag breaks from the folder on the Desktop, but if they are damaged, that could cause the problem to recur.

If this solves the issue, or doesn't, please email me to let me know.