Can you start in safe mode (hold Shift when launching TB)? If not, can you start in normal or safe mode if Windows is started in safe mode?

Hello

Thanks I tried those 2 suggestions but both same result, I get the "Crash Reporter" dialog box. Below is the report . Could I reinstall the previous version , or remove this one first ? Dont want to lose my setting and archive. Thanks

BIOS_Manufacturer: American Megatrends Inc. BlockedDllList: BreakpadReserveAddress: 124387328 BreakpadReserveSize: 83886080 BuildID: 20201019003438 CrashTime: 1604785159 FramePoisonBase: 0000004041080832 FramePoisonSize: 65536 InstallTime: 1604694623 MemoryErrorCorrection: None ModuleSignatureInfo: {"Kaspersky Lab JSC":["klhkum.dll"],"Microsoft Corporation":["VCRUNTIME140.dll","msvcp140.dll","D3DCOMPILER_47.dll"],"Microsoft Windows":["dbgcore.dll","avrt.dll","dbghelp.dll","dwmapi.dll","winnsi.dll","wsock32.dll","netprofm.dll","npmproxy.dll","dhcpcsvc6.DLL","dhcpcsvc.dll","amsi.dll","fastprox.dll","wbemsvc.dll","wbemcomn.dll","wbemprox.dll","msasn1.dll","winrnr.dll","nlaapi.dll","wshbth.dll","pnrpnsp.dll","NapiNSP.dll","usp10.dll","DWrite.dll","CRYPTBASE.DLL","d3d11.dll","ntmarta.dll","dxgi.dll","wldp.dll","windows.storage.dll","profapi.dll","mswsock.dll","dnsapi.dll","winmm.dll","uxtheme.dll","kernel.appcore.dll","IPHLPAPI.DLL","version.dll","userenv.dll","wtsapi32.dll","user32.dll","clbcatq.dll","oleaut32.dll","kernel32.dll","combase.dll","rpcrt4.dll","shell32.dll","ucrtbase.dll","ole32.dll","msvcrt.dll","psapi.dll","bcryptPrimitives.dll","msvcp_win.dll","sechost.dll","setupapi.dll","advapi32.dll","crypt32.dll","ws2_32.dll","wintrust.dll","gdi32full.dll","shlwapi.dll","msctf.dll","gdi32.dll","cfgmgr32.dll","imm32.dll","win32u.dll","SHCore.dll","KERNELBASE.dll","nsi.dll","bcrypt.dll","ntdll.dll","webauthn.dll"],"Microsoft Windows Hardware Compatibility Publisher":["antimalware_provider.dll"],"Mozilla Corporation":["thunderbird.exe","mozglue.dll","lgpllibs.dll","prldap60.dll","ldap60.dll","nss3.dll"]} MozCrashReason: Failed to get async shutdown service: NS_ERROR_FILE_NOT_FOUND ProductID: {3550f703-e582-4d05-9a08-453d09bdfdc6} ProductName: Thunderbird ReleaseChannel: release SafeMode: 0 SecondsSinceLastCrash: 263 StartupCrash: 1 StartupTime: 1604785158 ThreadIdNameMapping: 9676:"Gecko_IOThread",11916:"Link Monitor #1",16508:"Socket Thread",4396:"Permission",4400:"Timer",4364:"BackgroundThreadPool #1",4356:"JS Watchdog",8268:"JS Helper",8404:"JS Helper",8412:"JS Helper",8408:"JS Helper",8416:"JS Helper",10172:"JS Helper",4648:"JS Helper",4604:"JS Helper",4596:"BGReadURLs",4608:"Cache2 I/O",4792:"Cookie",4776:"Worker Launcher", Throttleable: 1 URL: UptimeTS: 11.662799999 Version: 78.4.0

This report also contains technical information about the state of the application when it crashed.

Hello

I tried both those methods and both failed with the same "Crash Reporter" message box, same as I get when I try to open Thunderbird as normal I did just now run MozBackup and the first attempt failed and said profile was corrupted. (it strangely firstly asked me to choose between 2 profiles "default" OR "default release" ,. Anyway I that seemed to crash and close so tried again, and now Mozback up is running (and the old Mozbackup box is still there as well) and looks like is backing up . (what it is backing up I dont know but hopefully my email archives etc)

The Backup using Mozbackup worked and seems to have save the settings and emails etc .It saved them as the new Thunderbird version ,not the previous version. Shall I try reinstalling the new version and hope that corrects the "corruption" ?

Well I simply reinstalled "over top" of old installation and it now works fine.(touchwood !!) Must have been corrupted somewhere along the line.

Glad to hear that. It's probably a good idea to exclude the TB profile folder from Kaspersky scanning and disable SSL connection scanning.

As for MozBackup, it hasn't been updated for years, so it can't be considered a reliable backup and restore option, especially since profiles are managed differently now in TB. Just backup the profile folder regularly by copying it to a safe location.

Hello Thanks I tried those 2 suggestions but both same result, I get the "Crash Reporter" dialog box.

Good to see progress. What are you crash IDs please? See https://support.mozilla.org/en-US/kb/mozilla-crash-reporter-tb