Trash bin is O/S issue not a FF issue.

Hi ann1026, a few other Mac users have reported this with Firefox 62. It's not clear why Firefox is leaving temp files/folders rather than cleaning them up normally. Apple's help article says: <blockquote>One or more Recovered Files folders may appear in your Trash after you restart your Mac.<br><br>The recovered files are temporary files used by macOS apps. Usually temporary files are deleted by an app when it no longer needs them. If an app quits unexpectedly, it may not be able to delete the temporary files before it quits. When you restart your Mac, macOS moves these temporary files to the Trash.</blockquote> ''From:'' https://support.apple.com/kb/PH25506 Is it possible your Firefox is not cleaning up completely between the time you Quit Firefox and then shut down your system? Have you gotten any shutdown crash dialogs (Mozilla Crash Reporter)? Maybe something in one of these other threads will provide inspiration, or consolation? * [https://support.mozilla.org/questions/1233846 Firefox recovery files found in trash] * [https://support.mozilla.org/questions/1232812 In my trash I see Documents being saved by firefox these are empty] * [https://support.mozilla.org/questions/1235870 What are these files firefox is creating in the trash and how do I stop it?] * http://forums.mozillazine.org/viewtopic.php?f=38&t=3041506