Firefox 15 isn't an "upgrade" (yet), it is a beta version of what will become Firefox 15 on 08-27 when it is released. Juniper Host Checker may not support "beta" browsers.

Then again, it might be an incompatibility which Juniper needs to deal with before Firefox 15 is released.

Thanks for the reply - I also tried downgrading to the latest production release of FF, and the behaviour was the same - I would get to the same point and FF would loop at the download prompt and not acknowledge when host checker was running. Don't know if FF isn't hearing something that Java or the Juniper is trying to tell it (security ?) or something, like you suggest, related to the Juniper software. One thing I will try is to install older versions of Java and see if that makes a difference - just in case.

• • • UPDATE: I found that downgrading FF had no effect - problem persisted. Then I downgraded from Java 7 update 5 to Java 6 update 33, and voilà ! Problem solved ! Observing more closely, under Java 7, the Juniper VPN routine flashed up a blurb that Java needed to be running; Under Java 6, no blurb and the coffee cup automatically appeared in my system tray. So, it would appear that either FF or Juniper VPN Host Checker has a very specific issue with Java 7 that only affects this specific situation. So, until something changes, I will have to remain with Java 6 if I want to stick with FF.