Hello,
Could you please send me more details to my support email (admin@fastaddons.com).
Ideally the specific webpage and exact steps, so that I could test it here.
Note that addons should not be able to crash the browser even if they wanted to, so it's quite unlikely my addon would do it.
If you lost your dials data somehow, there should be an easy way to recover them, more info here:
https://github.com/fastaddons/GroupSpeedDial/wiki/Recovery-of-your-dials,-how-are-dials-stored-and-how-to-make-a-backup
Best Regards,
Juraj Mäsiar