How to speedup slow Mozilla Thunderbird email client on Windows 7
I’ve experienced that Thunderbird has gotten slower and slower on my Laptop, at last it was nearly unusable. Sometimes I could see the chars appearing slowly on the screen while I typed the email or it was impossible to drag & drop a email to a different folder because Thunderbird was stalled for 10-15 seconds. No other applications on my System were slow and the notebook has afast harddisk and SSD, so this was not the problem. The following steps helped me to speedup Thunderbird so that it got usable again.
Set some interface options
Edit Thunderbird options under Preferences → Advanced → General tab, click on “Advanced options” button and set these values:
layers.acceleration.disabled = true
and
gfx.direct2d.disabled = false
and restart Thunderbird. If it is still slow, try the next options:
Disable AeroGlass
Disabling the AeroGlass interface makes the interface reacting much faster. Install the “NoGlass” Addon which is available in the Thunderbird addon repository.
Disable Folder Indexing
If you have folders with many emails inside, Indexing can slow down Thunderbird. Go To Preferences → Advanced → General tab and disable the Global search.
Antivirus scanning of the Email folders in the filesystem
A antivirus scanner can slow down Thunderbird as well. Configure your antivirus program to exclude the Thunderbird Mail folders from being scanned. Warning: this option should only be used when the email is scanned by a smtp proxy of the antivirus program for viruses before it is handed to Thunderbird.
Cleanup Thunderbird index files
Thunderbird creates a lot of index files. A cleanup of these files can speedup Thunderbird as well, especially if some of them are broken. There is a handy tool called ThunderFix to do that.
Thank You! Thank You! Thank You!
You ended days of endless frustration in one post
I am extremely grateful to you. If only all content on the internet was that useful and to the point 
All the best to you!
Worked for me too! Thanks!
Hi – sounds great, but where can I find ‘Preferences’ in the first place?
You saved my Thunderbird from being uninstalled
Thanks a lot!!!
HI!
In the newer version of Thunderbird, go to Tools / Options / Advanced / Config Editor.
Pat.
Many thanks for this. The one that did the trick was disabling Aeroglass. I know this because I tried all the other suggestions and still had a super laggy program that was driving me nuts. I also have a new Lenovo with SSD and tons of RAM. Enabling the NoGlass addon totally did the trick. You saved me from going crazy!
Typing anything in Thunderbird slowed down to where it would be 10 seconds before what I typed appeared on the screen. Without trying the other solutions, I ran ThunderFix. Everything works great now.
ThunderFix looks to be an older program, so I was concerned about using it on the current version of Thunderbird, but so far Thunderbird works fine and I haven’t found any problems.
Thanks for the great solution!
Thanks very much for that.
On my Win7 PC (TB 17.06) the gfx.direct2d.disabled = false seems to have made a lot of difference (the layers.acceleration.disabled was already true).
It’s gone dead slow again after doing all the stuff above.
It maybe add ons I use or the number of emails I have I guess..