I do a lot of my application testing in VMs, so when Firefox 39.0 came out, it went into my test environment and I built a new VM to check it out.
Firefox 39.0 looked like this when I launched it in my test VM.
As part of my testing workflow, I also installed Firefox 39.0 onto a couple of actual Macs.
Firefox 39.0 looked like this when I launched it on those machines.
As you can see, two very different results were discovered as part of my testing. After a few rounds of “It’s broken in the VM, retest, it’s still broken, retest on my laptop, no problem, repeat,” I finally tracked down a Mozilla bug report that indicated that the issue was not specific to my environment and gave me the potential scope of the issue. For more information, see below the jump.
Between the release of Firefox 38.0.5 and Firefox 39.0, Mozilla appears to have introduced a change that affected OS X VMs running on the following virtualization solutions for OS X:
It’s not mentioned in the Mozilla bug report, but my assumption would be that Firefox 39.0 running in OS X VMs on Parallels’ virtualization solution would also exhibit the same problem.
The scope presently appears to be limited to virtual machines running OS X as a guest OS. I tested Firefox 39.0 on the following OSs on physical Macs and the issue did not appear:
- OS X 10.9.5
- OS X 10.10.4
I also tested Firefox 39 on Windows 8.1 in a VMware VM and the issue did not appear.
