Since a week, Firefox won't start. This problem concerns only my wife's profile on our iMac (10.13.6). Firefox goes fine on my profile (administrator) and on a "test" profile I specially created to test Firefox. On my wife's profile (the problematic one), a crash report window appears every single time. I tried to boot in Safe mode. It is impossible to even boot that way. When I click the to start in Safe mode, the crash window appears. I deleted Firefox and reinstalled it. No solutions there either. I ran a malware detector. Flashback malware was detected and destroyed. Here is a copy of the detailed error message : AdapterDeviceID: 0x9488 AdapterVendorID: 0x1002 BuildID: 20181114214635 ContentSandboxCapable: 1 ContentSandboxLevel: 3 CrashTime: 1543160933 DOMIPCEnabled: 1 Email: EventLoopNestingLevel: 1 FramePoisonBase: 9223372036600930304 FramePoisonSize: 4096 InstallTime: 1543158751 Notes: FP(D00-L1000-W00000000-T000) WR? WR- OMTP? OMTP+3 ProductID: {ec8030f7-c20a-464f-9b0e-13a3a9e97384} ProductName: Firefox ReleaseChannel: release SafeMode: 0 SecondsSinceLastCrash: 333 StartupCrash: 0 StartupTime: 1543160930 TelemetryEnvironment: {"build":{"applicationId":"{ec8030f7-c20a-464f-9b0e-13a3a9e97384}","applicationName":"Firefox","architecture":"x86-64","buildId":"20181114214635","version":"63.0.3","vendor":"Mozilla","displayVersion":"63.0.3","platformVersion":"63.0.3","xpcomAbi":"x86_64-gcc3","updaterAvailable":true},"partner":{"distributionId":null,"distributionVersion":null,"partnerId":null,"distributor":null,"distributorChannel":null,"partnerNames":[]},"system":{"memoryMB":8192,"virtualMaxMB":null,"cpu":{"count":4,"cores":2,"vendor":"GenuineIntel","family":6,"model":37,"stepping":5,"l2cacheKB":256,"l3cacheKB":4096,"speedMHz":3060,"extensions":["hasMMX","hasSSE","hasSSE2","hasSSE3","hasSSSE3","hasSSE4_1","hasSSE4_2"]},"os":{"name":"Darwin","version":"17.7.0","locale":"fr-CA"},"hdd":{"profile":{"model":null,"revision":null},"binary":{"model":null,"revision":null},"system":{"model":null,"revision":null}},"gfx":{"D2DEnabled":null,"DWriteEnabled":null,"ContentBackend":"Skia","adapters":[{"description":null,"vendorID":"0x1002","deviceID":"0x9488","subsysID":null,"RAM":null,"driver":null,"driverVersion":null,"driverDate":null,"GPUActive":true}],"monitors":[{"screenWidth":1920,"screenHeight":1080,"scale":1}],"features":{"compositor":"none","gpuProcess":{"status":"unused"},"wrQualified":{"status":"blocked"},"webrender":{"status":"opt-in"}}},"appleModelId":"iMac11,2"},"settings":{"blocklistEnabled":true,"e10sEnabled":true,"e10sMultiProcesses":4,"telemetryEnabled":false,"locale":"fr","update":{"channel":"release","enabled":true,"autoDownload":true},"userPrefs":{"browser.search.widget.inNavBar":false},"sandbox":{"effectiveContentProcessLevel":3},"addonCompatibilityCheckEnabled":true,"isDefaultBrowser":null},"profile":{}} ThreadIdNameMapping: 9:"Gecko_IOThread",10:"Timer",11:"Socket Thread",12:"JS Watchdog",13:"JS Helper",16:"JS Helper",15:"JS Helper",14:"JS Helper",19:"Cache2 I/O",20:"Cookie",22:"GMPThread",23:"Compositor",24:"VRListener",25:"ImgDecoder #1",26:"ImageIO",27:"IPDL Background",30:"DOM Worker",34:"StyleThread#1",33:"StyleThread#0",35:"StyleThread#2",37:"StreamTrans #21",34:"StreamTrans #22",35:"StreamTrans #23",38:"ImageBridgeChild", Throttleable: 1 UptimeTS: 3.46586205 Vendor: Mozilla Version: 63.0.3 useragent_locale: fr Thanks for nay advice that could help me solve this problem.