I have 2 MacBookPro's that both experience the issue For sake of testing: I access this website and it does not load properly in Firefox v59+ https://cesiumjs.org/Cesium/Apps/HelloWorld.html The last Firefox version that this does work on is Firefox v58.0.2 In both versions (while working and not working) I receive this message in the developer console "Error: WebGL warning: getContext: Disallowing antialiased backbuffers due to blacklisting." It works in all other browsers on the same computers. My windows computers do not experience this issue. Please let me know how I can find out why the page no longer loads after v58.0.2. I have had to stop upgrading my Firefox version after 58.0.2 and now the upgrade messages are getting in the way so I would love to upgrade. Please help me determine what was done after 58.0.2 that is causing a conflict on these machines. Thank you. OS X El Capitan, version 10.11.6 MacBook Pro (17-inch, Late 2011) Processor 2.5 GHz Intel Core i7 8 GB 1333 MHz DDR3 Graphics AMD Radeon HD 6770M 1024 MB