how many of those o365 accounts use the owl addon? Does it reproduce in safe mode?

Hi Matt,

Thank you for your reply.

Actually none of the accounts are using the owl addon. Yes I can reproduce the problem in troubleshoot mode. It seems a little bit faster though when I have enabled it.

EDIT: I have downgraded to the stable release and in safe mode it works as it should be. Also the CPU utilization remains @ 20%.

91 is the stable release... but it went through about 6 betas before release. Is that what you have "downgraded to"

Yes. I am on the 91st version right now which is the latest stable as you said.

Do I need to use owl for the 0365 accounts in order for thunderbird to work properly? Because as far as I can see the only way for thunderbird to work properly is when I am using it on troubleshoot mode.

EDIT: I created a new profile and added only my personal Gmail. The problem showed up again. Owl and Exquilla are not compatible with Thunderbird 91.

In the whole of the past year of testing, I'm not aware of slow scrolling being reported in Windows. But there have been a couple reports by Mac users.

Do you have smooth scrolling enabled?

Yes it is enabled. I disabled it, restarted thunderbird, but unfortunately the problem remains.

EDIT: I uninstalled thunderbird and removed the profile folder and other installation folders (as many as I could find), but nothing changed. I really can't understand what is wrong with it. On my Ubuntu installation thunderbird works with no problems at all. So I guess it must be something on my Windows 10 installation?

If it only happens in the Folder pane, it is likely a Thunderbird bug.

Oh ok. Should I report it? If yes where can I do that?

OK. I found the source of the problem. Actually not me. A user named jim_p from adslgr.com. The problem lies to webrender. If I go to preferences --> config editor and search for the entries:

• gfx.webrender.all
• gfx.webrender.force-disabled

Switch the first one to false (it was already switched to false) and the second one to true (I switched this one manually) everything works smooths and no cpu usage jumps happen. Actually he explained to me that in troubleshoot mode webrender is turned off by default that is why I see the improvement. So my question is: is this a bug or something that my computer does because it is old?

I replied back with a solution but for some reason my reply has to go through moderation inspection. If a mod can review my reply and approve that would be helpful.

What exactly is smooth looking? Where can I find this option?

This problem is not Windows-specific. I have the same problem under Linux (Manjaro, 64bit). Thunderbird is almost not useable anymore, scrolling in the folder pane is a pain, moving emails to folders takes ages. So SLOOOOW!

I tried to downgrade to the previous version 78.14, but version 91 has a new profile format! A downgrade would mean losing all setiings, account information,e verything from scratch. What a bullshit!!

If this persist, I will say Good Bye to Thunderbird.

If you execute: thunderbird -p --allow-downgrade, doesn't this solve the issue when rolling back to 78th version?

If you're having this problem please use the blue button "I HAVE THIS PROBLEM TOO" at the top of this page to indicate it.

I've found a bug report about this, I've added the possible workaround :

https://bugzilla.mozilla.org/show_bug.cgi?id=1730423

It would be very useful for several people to test this and report back here or in the bug report.