Hi denis, it's true, all the pinned tabs load automatically when you restore your previous session. But luckily there is a preference for that. Could you test this change:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

(2) In the search box above the list, type or paste demand and pause while the list is filtered

(3) Double-click the browser.sessionstore.restore_pinned_tabs_on_demand preference to switch the value from false to true -- so they will behave like regular tabs and only load when activated

The similarly named browser.sessionstore.restore_on_demand preference is for the regular tabs and should retain its default value of true if you don't want them to all load.

Success?

Hi Jeff, thanks for your help. I can see those pined tabs are no longer loaded on start. Best Regards