I'm currently using MacOS 15.4.1 Sequoia with FireFox 138.0.1. It works fine after updating from 138.0.0 on my primary (Administrator) account. However, there is a second User account on this MacBook Pro laptop, used by other family members. All is not well here... Firefox updated itself from 137.0.0 recently and now will not run on the User account. On startup, it asks for an Administrator password to install a Helper tool and then will proceed no further. I have tried :- Making the User account into Administrator - still hangs Cancel and re-start FireFox - hangs! Re-start the MacBook from cold - hangs! Cleaned Firefox installation and folders in the User Library (both User and Administrator) - still hangs! I'm aware there are two Library folders, one each for the System and one for each user, didn't touch the System Library. Added a new User account - it works! So maybe something in the System Library is the culprit? I've always regarded that area as "off limits" to us mere mortals, so please, not the "Wipe it and Start Again" option. I don't really want to kill the User account, there is a lot of data in there and surely will miss something important if I delete it. Summary, 137.0.0 worked, it updated to 138.0.1, it hangs up! I am unable to fix it. Any offers guys?