So only your times are gone, sessions and all your options are still there? And the times in all of your sessions are gone? If it was just one session, I'd guessed you maybe accidentally deleted them (alt+d + enter clears all the times in one session), but if all times in all sessions are gone that's pretty unlikely to happen accidentally. When you do a solve now, does it show in the list? Is the solve number for the first new solve 1 or is there maybe an error that it just doesn't show previous solves?
I lack the knowledge to really help you, but if you didn't clear your cookes, maybe the developer can, if it's really a bug. You can try to open an issue on github, if he doesn't answer here.
https://github.com/cs0x7f/cstimer/issues
Just a tip for the future - if you make a bug report and/or want help (in general, not necessarily cubing related):
Try to give as much useful information as you can and try to be very specific.
is not a good way. Not a nice tone, very few and not very unambiguous information. If I was a dev, it could be that I'd ignore a comment like yours.