1640725 - Windows Defender - "Antimalware Service Executable" (ASE) overloaded CPU when Thunderbird runs with last version

Status: RESOLVED INVALID

(Thunderbird :: Mail Window Front End, defect)

Description

[hp.mob]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:76.0) Gecko/20100101 Firefox/76.0

Steps to reproduce:

I start Thunderbird 68.8.1
As soon as I go to the main page tohave a look on my mails, I can notice on task manager that "Antimalware Service Executable" (ASE) becomes very active so that I finally can not use Thunderbird. If I endThunderbird, the ASE go back to quite.

Actual results:

As described, my big thunderbird (3 bigs mailbox) is unusable because when running, ASE becomes active with high level of CPU due to Thunderbird

Expected results:

Thunderbird should not make ASE very active for hours and hours if I don't kill Thunderbird !

Comment 1

[hp.mob]

was the same with 68.8.0

I have a second installation of Thunderbird with smaller mailboxes which run fine.

Comment 2

[Wayne Mery (:wsmwk)]

In options > advanced > general > is "allow windows search" enabled, or disabled?

Comment 3

[hp.mob]

Thanks for answer

"allow windows search", in French "Autoriser recherche Windows à rechercher dans les messages" is disabled.
And can not be enabled ( since I disabled service "windows search" ! )

rgds
h/p

Comment 4

[Wayne Mery (:wsmwk)]

Does https://superuser.com/questions/1324436/system-slow-unresponsive-when-thunderbird-is-receiving-emails-with-windows-defen help?

Comment 5

[hp.mob]

Sorry but Windows Defender is OFF .
The trouble is with AntiMalware Service . Since release from the 22th of May.

Comment 6

[Wayne Mery (:wsmwk)]

They are one and the same https://www.howtogeek.com/318556/what-is-antimalware-service-executable-and-why-is-it-running-on-my-pc/ so I don't know why you are seeing what you are reporting.

I don't have a system running defender to test with.

Comment 7

[hp.mob]

So, this morning, after a night with Thunderbird running on my 3 big email boxes, the PC is now OK.
I noticed some very large folders and also that Thunderbird was reloading all my folders from the IMAP server.
So IMO it me explains the load in // of ASE to check content reloaded.
I don't know why Thunderbird decided to resynchronize all my emails

So, would say be careful with large and numberous email boces
Thanks.

Comment 8

[Anje]

I have Windows 10, but do not use 'Defender'. I can confirm that Antimalware Service Executable file name is MsMpEng.exe. There are plenty of reports about this service hogging CPU and not exclusive to thunderbird as it scans all files, so files being opened and/or downloading of files over the internet to your computer could be subject to scanning. There are other reasons including high CPU after a windows update. It is not a Thunderbird bug and perhaps should have been asked in the Support Forum. This is a Windows Defender issue. I suggest you access Defender and exclude thunderbird files from being scanned and also check out the timing for scheduled scans. Suggest queries about this to be asked in the Microsoft Windows Forums.

Comment 9

[Wayne Mery (:wsmwk)]

Another resource https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues