I had a weird problem today with a new Macbook pro : Firefox 3.6.10 was installed on it, and the JVM would never start, no matter how I changed the Java preferences. There was no error message. It worked well with Safari. I checked everything, but this was a brand new install of MacOS X (10.6.3 followed by an update to 10.6.4 which didn't fix the problem), with a new user, and a new install of Firefox.

Finally, I installed an old version of Firefox (the latest 3.5), and it started working, even with Firefox 3.6.10. So, it seems the launching of the JVM expects something coming from older versions of Firefox, but I have not found what.

As more and more people install the latest Firefox version on new Macs, this bug is likely to hit more and more people. Unless there was something strange on the computer I was using…