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


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.

39 thoughts on “How to speedup slow Mozilla Thunderbird email client on Windows 7”

  1. 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!

    • I have no idea what version of TB is the author using but in newer versions there is no “preferences.” Not you need to access: tools>options>general>advanced configuration>config editor.

  2. 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!

  3. 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!

    • I am not exactly sure what Thunderfix does, but after running it, my inbox is downloading (slowly) all 5200 messages that were already there. Perhaps this is something to be aware of for those who have Google mail and a large number of emails in their IMAP folders.

      • This happened to me too, help! is there anything I can do to fix this? It keeps on downloading all emails again and again and I can´t do anything!

  4. 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).

  5. 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..

  6. > ThunderFix looks to be an older program, so I was concerned about using it on the current version of Thunderbird,

    ThunderFix simply deletes files and doesn’t depend on anything substantial in Thunderbird, thus not affected by version changes. But it’s also just a hammer – *IF* it helps (it’s not guaranteed to help), it doesn’t FIX what cased the breakage in the first place.

    n.b. support website

  7. tunately none of the listed options helped me out. (Except that I didn’t dare to try swithcing off the virus scanner.)
    But….I found another solution, that worked extremenly well!

    Step 1. I moved all Inbox messages to a newly created LOCAL folder IN THUNDERBIRD.
    Step 2. I closed Thunderbird.
    Step 3. I then moved the Inbox and Inbox.msf, AT THE EXPLORER LEVEL, to another folder. (Not relevant where. I just kept it in case I would need it againg later, which I didn’t.)
    Step 4. I restarted Thunderbird.
    Surprise, surprise: The Inbox now worked perfect and very quick.
    However, sending a message was still extremely slow. Not the actual sending,
    but placing it in Sent items.
    Step 5. I moved all Sent messages to a newly created LOCAL folder IN THUNDERBIRD.
    Step 6. I closed Thunderbird.
    Step 7. I then moved the Sent and Sent.msf, AT THE EXPLORER LEVEL, to another folder. (Not relevant where. I just kept it in case I would need it againg later, which I didn’t.)
    Step 8. I restarted Thunderbird.
    Surprise, surprise: Thunderbird now works quicker and better than ever before!!!.
    Because I didn’t dare to do all this, the whole process took me several days. I wish I had had the courage sooner. It is a miracle and again fun to use Thunderbird!

  8. Disabling AeroGlass speeded up my Thunderbird a lot. It used to freeze for seconds, even for minutes sometimes, when moving messages from the inbox into a subfolder.
    And I also used ThunderFix. I will see if Thunderbird runs like a well-oiled machine in the future or if it slows down again.

  9. I suddenly got a very slow thunderbird, so checked the interface options. The layers.acceleration.disabled=true was set okay, but the dfx.direct2d.disabled=false was set to true, so I changed it to false. Restarted my laptop as advised but it will not open, a complete blank screen. I am running windows eight and have to get a safe start but without any luck. Help, anyone got any suggestions.

  10. I just really wanted to say a big thank you! The Thunderbird loaded as if it was a new account, downloading folders again and such and the difference in performance far surpasses any scare of losing add on enhancements. I have this add on that allows for all these extra doctored up folders along the top and at first there was a little glitch scare that I’d lost them. But they reappeared and everything there back to normal, except the speed is WAY more snappy! Thanks a bunch! And for having 56,000 mails in my All mail, as a Realtor, you can imagine how both impossible I thought this was and also delightful. I really was not that slow, but now I know I WAS. I think because I had not compacted any folders from the beginning of time, made me prone to the bloat I was experiencing, even though I had already compacted them, it did not do as good as this did. Productivity has gone up in an area where you do or die, as I live by my email. Thanks a mill!

  11. Woah, this worked. Thunderbird was driving me nuts, I was ready to jump ship. I put in a new SSD and the performance just kept getting worse.

    Thank you!

    Win7 – Thunderbird 31.5.0

  12. Hi all,
    My company and branches are using Thunderbird mail, but a couple of recent days, when my co-worker sent me an email from Japan to Vietnam, I took 30 minutes to receive that email(the mail just have 10MB attached files). In the past, it worked normally, I don’t know why, I checked the Internet connection but it worked normal. When I try to send an email to Japan, nothing happen. The problem is receiving mail was slowly. Could anyone know please do tell me? I will appreciate. Thanks in advance!

  13. Being one of the strange people that use a Mac, I also find that Thunderbird has got really slow. I wanted to try Thunderfix, but it’s not Mac compatible (it’s an exe file).
    It’s also not clear to me where the “Thunderbird repository” is (on a Mac) so I can disable “no glass”.
    Any ideas please?

  14. Thank you for the ThunderFix hint. This was just the ticket. I had been operating under the assumption that it was related to my virus/spam scanners (either being inadequate and letting viruses in or being over-diligent). ThunderFix repaired it immediately!

  15. This helped me a lot: If you are using Gmail with an IMAP account, unsubscribe the “All Mail” folder, unsubscribe it, exit, and then delete both “All Mail.” and “All Mail.msf”. The All Mail folder may double the amount of disk space used by Thunderbird.”

    May I disable anti-virus when I am using Thunderbird with Gmail?

  16. Tremendously helpful: Windows explorer to C:\USERS RIGHT click on your account and choose “Properties” In the General tab, select the Advanced button Uncheck the box “Allow files in this folder to have contents indexed in addition to file properties” Select OK, and then select APPLY When asked, allow this to apply this to all sub-folders. Click OK to close this window. THIS WILL STOP THE HIDDEN APPS FOLDER FROM BEING INDEXED, WHICH WILL STOP WINDOWS FROM INDEXING YOUR EMAILS (which is the cause of the problem). Next, go into your account folder and select just the folders you want indexed. Repeat the above process of those folders (this time choosing to index the the folder and its sub-folders).

  17. None of the suggestions work. Moving folders seems terribly complicated. Why hasn’t the Mozilla crew fixed this in the newest update?

  18. Your suggestions helped me solve my problem of Thunderbird being very slow to download emails from my email provider’s IMAP server. I set gfx.direct2d.disabled = false and Disabled Folder Indexing and now it seems to download emails at a speed similar to Outlook. Many thanks !!!

  19. Hi, Thunderbird runs correctly but when I select a list of e-mails (even small) to assign a color (eg. pressing 5), it makes me wait for at least 1-2 minutes… I have a very fast computer: what could be the problem? Thanks!


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