> putting 0 on the "Dom.max_chroms_script_run_time" will avoid the pop up but not the long time for haviing the control of thunderbird

right. this is not a solution.

A better safe mode test (it is helpful to do both at the same time)...

Start *Windows'* safe mode with networking enabled - win10 https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode Still In Windows safe mode, start thunderbird in safe mode - https://support.mozilla.org/kb/safe-mode-thunderbird

Does problem go away?

thanks Wayne Mery for responding,

As suggested, I have tried windows and Thunderbird both on safe mode and I got the same answer : the pop-up about chrome......js not responding at the right speed..my value is 10s right now. I can increse it to 20s

Have you another guess ? is it possible that the size of my different local mail folders a problem? the full "Local folders" is around 13.Go and one file is arong 1.1Go

Please have a look at this larger list https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems and post your results.

I have looked at the long list of test-steps and my problem is still present 1: yes 2 : tried :same results 3: tried :same results 4: no 5 : no 6 : all search disabled 7! no 8: not yet check on the way : same as 16 9: no 10: tried :same results 11 one between 2 and 3Gb 4 close to 1Gb 12 it is only the starting 13 no 14: no 15 346ko 16: done but don't know how to look at the log entries??? 17 :no 18 no 19 no 20 no 21 no 22 yes few filters 23 lot of RAM , HDD and CPU available 24 : windows case 25-26 maybe on the way....

Do you use McAfee ? https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues#McAfee

no I am using Norton security 22.11

Ps the log file is empty with the MOZ option MSGDB

re :Fall creators 1709 update

Did this slowdown occur/get worse after this update ?

The answer is fully YES... I start to get this error due to a time out only after this fall creator update.

Please tell uis what you have here: 'Menu icon' > 'Options' > 'Options' > 'Advanced' > 'Network & Disk Space' tab By default this setting is usually selected: “Use system proxy settings”.

Do you have this setting?

No it is on "automatic detection of the proxy parameters for this network" or something similar.. it is my traduction of my french option!

re :I start to get this error due to a time out only after this fall creator update.

Yes there are a lot of various complaints if you search on google.

Do you need that update ?

Info on removal: https://answers.microsoft.com/en-us/windows/forum/windows_10-windows_install-winpc/how-can-i-uninstall-windows-10-fall-creators/358224cb-20ad-43f2-aa7b-b788c2db1169?auth=1

Yes I guess that it is neded for avoiding the SMB V1.0 protocole securising the Wifi recently detected vulnerability.

So up-to-now, this long starting is annoying but I prefer security of Windows versus saving 20 secondes in thundebirfd

a complementary information about my slow starting : if I uncecked all the automatic readings new mails at starting thunderbird starts 'normally'.

is a special configuration of an imap account can freze or slow down heavily the sarting?