Unsure if this is helpful but I experience this issue on every startup typically *except* the startup following an upgrade. Yesterday, I noticed that it actually only seems to occur when my monitor is set to its maximum refresh rate (300hz) and doesn't occur at 240hz or 60hz (the other supported modes). Literally I can open firefox, experience the hang, close firefox, change the refresh rate, and the hang will not occur on next open. Likewise, it returns if I set the refresh rate to 300. Hopefully that's helpful, and not just a description of a different bug with symptoms! https://bugzilla.mozilla.org/show_bug.cgi?id=1734947#c22
Bug 1567863 Comment 102 Edit History
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Unsure if this is helpful but I experience this issue on every startup typically *except* the startup following an upgrade. Yesterday, I noticed that it actually only seems to occur when my monitor is set to its maximum refresh rate (300hz) and doesn't occur at 240hz or 60hz (the other supported modes). Literally I can open firefox, experience the hang, close firefox, change the refresh rate, and the hang will not occur on next open. Likewise, it returns if I set the refresh rate to 300. Hopefully that's helpful, and not just a description of a different bug with the same symptoms! https://bugzilla.mozilla.org/show_bug.cgi?id=1734947#c22