[Polylactic_acid]

I had an issue where every time I restarted firefox it would lose my umatrix data.

[RealStickman_]

Sorry to ask, but you clicked the padlock, right?

[Polylactic_acid]

Nope. Is that how you save?

[RealStickman_]

Yes. Otherwise everything will be lost when you close the browser.

[xaqfox]

There is also a cloud backup feature in the options if you are into that sort of thing.