hi Nossi78, thanks for providing a crash report id. we have seen quite a number of similar reports about this issue in the last hours and this issue is likely caused by your symantec security software that is hooking into firefox (probably through a program/signature update done by them). other users reported that updating firefox in this situation helped with the crashes. you can download & install the latest firefox (german) from https://download.mozilla.org/?product=firefox-48.0.2-sha1&os=win&lang=de

I have de-installed Firefox and re-isntalled the latest version. Didn't help. Same problem.

Yes i have Norton 360 Premier. But it updated several days ago. No problems then. Only today Firefoxs doesn't start.

can you please reply with the latest crash report id generated after the update then?

I suppose this one?

AdapterDeviceID: 0x0615 AdapterDriverVersion: 9.18.13.4181 AdapterSubsysID: 040110b0 AdapterVendorID: 0x10de AvailablePageFile: 6192721920 AvailablePhysicalMemory: 1832071168 AvailableVirtualMemory: 3932098560 BIOS_Manufacturer: Dell Inc. BlockedDllList: BreakpadReserveAddress: 235864064 BreakpadReserveSize: 67108864 BuildID: 20151216175450 CrashTime: 1473796038 EMCheckCompatibility: true EventLoopNestingLevel: 1 FramePoisonBase: 00000000f0de0000 FramePoisonSize: 65536 InstallTime: 1473791691 Notes: AdapterVendorID: 0x10de, AdapterDeviceID: 0x0615, AdapterSubsysID: 040110b0, AdapterDriverVersion: 9.18.13.4181

ProductID: {ec8030f7-c20a-464f-9b0e-13a3a9e97384} ProductName: Firefox ReleaseChannel: release SafeMode: 1 SecondsSinceLastCrash: 1904 StartupTime: 1473795988 SystemMemoryUsePercentage: 56 TelemetryEnvironment: {"build":{"applicationId":"{ec8030f7-c20a-464f-9b0e-13a3a9e97384}","applicationName":"Firefox","architecture":"x86","buildId":"20151216175450","version":"43.0.1","vendor":"Mozilla","platformVersion":"43.0.1","xpcomAbi":"x86-msvc","hotfixVersion":"20150311.01"},"partner":{"distributionId":null,"distributionVersion":null,"partnerId":null,"distributor":null,"distributorChannel":null,"partnerNames":[]},"system":{"memoryMB":4029,"virtualMaxMB":4096,"isWow64":true,"cpu":{"count":4,"cores":4,"vendor":"GenuineIntel","family":6,"model":15,"stepping":11,"l2cacheKB":4096,"l3cacheKB":null,"speedMHz":2660,"extensions":["hasMMX","hasSSE","hasSSE2","hasSSE3","hasSSSE3"]},"os":{"name":"Windows_NT","version":"6.0","servicePackMajor":2,"servicePackMinor":0,"installYear":2014,"locale":"de-DE"},"hdd":{"profile":{"model":"Hitachi HDS721616PLA380","revision":"P22OAB3A"},"binary":{"model":"Hitachi HDS721616PLA380","revision":"P22OAB3A"},"system":{"model":"Hitachi HDS721616PLA380","revision":"P22OAB3A"}},"gfx":{"D2DEnabled":false,"DWriteEnabled":false,"adapters":[{"description":"NVIDIA GeForce GTS 250","vendorID":"0x10de","deviceID":"0x0615","subsysID":"040110b0","RAM":1024,"driver":"nvd3dumx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um","driverVersion":"9.18.13.4181","driverDate":"8-17-2015","GPUActive":true}],"monitors":[{"screenWidth":1920,"screenHeight":1080,"refreshRate":60,"pseudoDisplay":false}],"features":{"compositor":"none","d3d11":{"status":"blocked"},"d2d":{"status":"unavailable","version":"1.0"}}}},"settings":{"addonCompatibilityCheckEnabled":true,"blocklistEnabled":true,"isDefaultBrowser":true,"e10sEnabled":false,"telemetryEnabled":false,"isInOptoutSample":false,"locale":"de","update":{"channel":"release","enabled":true,"autoDownload":true},"userPrefs":{"app.update.service.enabled":false,"browser.cache.disk.capacity":358400,"browser.newtabpage.enhanced":true,"extensions.blocklist.enabled":true,"extensions.blocklist.url":"https://blocklist.addons.mozilla.org/blocklist/3/%APP_ID%/%APP_VERSION%/%PRODUCT%/%BUILD_ID%/%BUILD_TARGET%/%LOCALE%/%CHANNEL%/%OS_VERSION%/%DISTRIBUTION%/%DISTRIBUTION_VERSION%/%PING_COUNT%/%TOTAL_PING_COUNT%/%DAYS_SINCE_LAST_PING%/","extensions.update.url":"https://versioncheck.addons.mozilla.org/update/VersionCheck.php?reqVersion=%REQ_VERSION%&id=%ITEM_ID%&version=%ITEM_VERSION%&maxAppVersion=%ITEM_MAXAPPVERSION%&status=%ITEM_STATUS%&appID=%APP_ID%&appVersion=%APP_VERSION%&appOS=%APP_OS%&appABI=%APP_ABI%&locale=%APP_LOCALE%&currentAppVersion=%CURRENT_APP_VERSION%&updateType=%UPDATE_TYPE%&compatMode=%COMPATIBILITY_MODE%","extensions.update.background.url":"https://versioncheck-bg.addons.mozilla.org/update/VersionCheck.php?reqVersion=%REQ_VERSION%&id=%ITEM_ID%&version=%ITEM_VERSION%&maxAppVersion=%ITEM_MAXAPPVERSION%&status=%ITEM_STATUS%&appID=%APP_ID%&appVersion=%APP_VERSION%&appOS=%APP_OS%&appABI=%APP_ABI%&locale=%APP_LOCALE%&currentAppVersion=%CURRENT_APP_VERSION%&updateType=%UPDATE_TYPE%&compatMode=%COMPATIBILITY_MODE%","general.smoothScroll":false,"gfx.direct2d.disabled":true,"layers.acceleration.disabled":true,"xpinstall.signatures.required":false}},"profile":{}} Theme: classic/1.0 Throttleable: 1 TotalPageFile: 8674553856 TotalPhysicalMemory: 4224405504 TotalVirtualMemory: 4294836224 URL: Vendor: Mozilla Version: 43.0.1 Winsock_LSP: MSAFD-Tcpip [TCP/IP] : 2 : 1 :

MSAFD-Tcpip [UDP/IP] : 2 : 2 : %SystemRoot%\system32\mswsock.dll 
MSAFD-Tcpip [RAW/IP] : 2 : 3 :  
MSAFD-Tcpip [TCP/IPv6] : 2 : 1 : %SystemRoot%\system32\mswsock.dll 
MSAFD-Tcpip [UDP/IPv6] : 2 : 2 :  
MSAFD-Tcpip [RAW/IPv6] : 2 : 3 : %SystemRoot%\system32\mswsock.dll 
RSVP-TCPv6-Dienstanbieter : 2 : 1 :  
RSVP-TCP-Dienstanbieter : 2 : 1 : %SystemRoot%\system32\mswsock.dll 
RSVP-UDPv6-Dienstanbieter : 2 : 2 :  
RSVP-UDP-Dienstanbieter : 2 : 2 : %SystemRoot%\system32\mswsock.dll

useragent_locale: de

this is still coming from an old firefox 43.0.1 - please specifically use the link that i have provided in my prior reply to download firefox 48.0.2 (as it may currently not be served to xp and vista users on the default download page due to a different issue)!

Ah. Now i have used your specific link. Default download page shows only firefox 43.0.1. Now i have 48.0.2 and it seems to work. Thank you :)