On a legacy iMac with over ten years of Firefox usage, I suddenly cannot sign in. The mac caps out at High Sierra 10.13.6 and I am unable to activate sync. I have tried allowing all cookies, restarting the browser several times, and even explored the config files.... to no avail. How do I "enable local storage"? that's the error that sync provides me, but there is no option to fix that and all of your help files point me to cookies information (which I have done everything with). There are no actual help files to fix the local storage problem. This is frustrating! Do I have to uninstall the entire application? If so, how to I preserve my bookmarks and pws without also porting over whatever is broken in the application?