Even though I cannot run LW 4.18 in 'any' account, my LW 4.16 did stop working in one account, so as I explained to you privately, I copied across the LW & Java preferences from one account to the other (needed to change user permissions first so they were both read & write by the main account user), and alas LW 4.16 started working again. But surprising LW 4.18 has been dead in all of my accounts. But dead was how 4.16 was in the main account for a short time. I guess there's always the possibility of installing OSX on a different drive & see if it works in there. O.o

It's done; installed OSX on a different partition. Just the basics of the installer with no updates (or any multimedia apps). Installed LW 4.18 Basic, it ran with no problems. Installed Pro, it also ran with no problems. Made a copy of both user & library preferences. Question is, is the problem with preferences or original OSX installation. I have reinstalled OSX on this mac several times since February so I somehow doubt that's the problem. Stief, perhaps you can advise which preferences might be the trouble-some one(s).

BTW I used the same download folder & it actually started downloading a file by itself. LW on this account is installed on a different drive. The one in the account/new installation was installed in the default app's folder. However, I did also try installing there on this & other accounts with no success with 4.18 so I'm not sure that is a problem or not. It should not be. Oh but I just realised my old incompletes didn't reload which is not super surprising considering I downgraded. np A file started downloading 5 secs after resuming them, & another 30 secs later.