That sounds like a message from an addon. Do you perhaps have tbsync addon installed.

yes I have tbsync, and not sure what it actually does. The problem is that I can't even check as the program crashes within few seconds after opening.

If you are seeing the crash reporter https://support.mozilla.org/en-US/kb/mozilla-crash-reporter-tb#w_when-thunderbird-crashes please visit Help > Support to find your crash IDs and post them here.

Thanks Wayne, As there are many crash reports, I took a printscreen in the attachment to this message

Thanks for the support!

Vincent

NB: I tried to restart in safe mode pressing the shift key but it still crashed: see the details below BuildID: 20241210220830 Comments: Hi I tried to start thunderbird in safe mode by pressing "shift" key when starting. I could get the icon to disable all addons, I clicked but then Thunderbird still crashed.

Kindly assist CrashTime: 1737190925 InstallTime: 1735064667 ModuleSignatureInfo: {"Bitdefender SRL":["gemmauf32.dll","atcuf32.dll","bdhkm32.dll"],"Microsoft Windows":["BitsProxy.dll","cscapi.dll","ntshrui.dll","OneCoreCommonProxyStub.dll","linkinfo.dll","Windows.StateRepositoryPS.dll","edputil.dll","msvcp110_win.dll","policymanager.dll","BCP47mrm.dll","windows.staterepositoryclient.dll","MrmCoreR.dll","CoreUIComponents.dll","CoreMessaging.dll","ondemandconnroutehelper.dll","windows.staterepositorycore.dll","Windows.System.Launcher.dll","AudioSes.dll","MMDevAPI.dll","OneCoreUAPCommonProxyStub.dll","explorerframe.dll","xmllite.dll","directmanipulation.dll","Windows.Security.Integrity.dll","devobj.dll","avrt.dll","Bcp47Langs.dll","Windows.Globalization.dll","twinapi.dll","mscms.dll","dcomp.dll","Windows.UI.Immersive.dll","Windows.UI.dll","npmproxy.dll","netprofm.dll","dhcpcsvc.dll","dhcpcsvc6.DLL","Microsoft.Internal.WarpPal.dll","wscapi.dll","winnsi.dll","wshbth.dll","nlansp_c.dll","winrnr.dll","twinapi.appcore.dll","dataexchange.dll","usp10.dll","dbgcore.dll","WinTypes.dll","Windows.FileExplorer.Common.dll","DXCore.dll","NapiNSP.dll","directxdatabasehelper.dll","dxgi.dll","DWrite.dll","d2d1.dll","WindowsCodecs.dll","comctl32.dll","propsys.dll","ktmw32.dll","wsock32.dll","textinputframework.dll","FWPUCLNT.DLL","thumbcache.dll","rasadhlp.dll","dnsapi.dll","mswsock.dll","CRYPTBASE.DLL","bcrypt.dll","iertutil.dll","winsta.dll","umpdc.dll","msasn1.dll","wininet.dll","powrprof.dll","profapi.dll","sspicli.dll","ntmarta.dll","dwmapi.dll","version.dll","windows.storage.dll","kernel.appcore.dll","dbghelp.dll","srvcli.dll","netutils.dll","winhttp.dll","IPHLPAPI.DLL","cfgmgr32.dll","winmm.dll","GdiPlus.dll","oleacc.dll","wtsapi32.dll","uxtheme.dll","msimg32.dll","shlwapi.dll","ucrtbase.dll","gdi32.dll","combase.dll","clbcatq.dll","SHCore.dll","user32.dll","kernel32.dll","ole32.dll","shell32.dll","ws2_32.dll","nsi.dll","KERNELBASE.dll","wintrust.dll","advapi32.dll","sechost.dll","setupapi.dll","gdi32full.dll","msvcp_win.dll","psapi.dll","crypt32.dll","msctf.dll","rpcrt4.dll","msvcrt.dll","oleaut32.dll","win32u.dll","bcryptPrimitives.dll","imm32.dll","ntdll.dll","AppxDeploymentClient.dll","AppxDeploymentClient.dll","resourcepolicyclient.dll","dxcore.dll","KBDBE.DLL"],"Microsoft Windows Software Compatibility Publisher":["VCRUNTIME140.dll","msvcp140.dll"],"Mozilla Corporation":["thunderbird.exe","rnp.dll","xul.dll","gkcodecs.dll","freebl3.dll","nss3.dll","nssckbi.dll","softokn3.dll","lgpllibs.dll","mozglue.dll"]} ProductID: {3550f703-e582-4d05-9a08-453d09bdfdc6} ProductName: Thunderbird ReleaseChannel: esr StartupTime: 1737190891 SubmittedFrom: Client Throttleable: 1 UptimeTS: 34.0 Vendor: Version: 128.5.2 WindowsErrorReporting: 1 This report also contains technical information about the state of the application when it crashed.

A current problem with Windows users is bitdefender causing crashes. And I see you use bitdefender - download from https://www.thunderbird.net/en-US/download/esr/ and reinstall.

If that doesn't help and you are seeing the crash reporter please visit Help > Troubleshooting Information to find your crash IDs and post them here, as text please.

Thanks a lot Wayne, I did reinstall and it seems to be working, thanks a lot!

Vincent