[Trainer-Talk] Thunderbird vs. Outlook Classic - my own real-world comparison with optimization tips for screen reader users

Raul Gallegos - RGA raul.gallegos at rgats.com
Mon Jun 8 18:01:54 UTC 2026


Hello everyone,

I've been following the discussion regarding New Outlook vs. Classic 
Outlook, and since I mentioned that I've been leaning heavily into 
Thunderbird lately, I wanted to share some concrete data regarding the 
"large space issue" that often scares people away from it.

I did a direct comparison on my machine. I have the exact same 5 Google 
email accounts configured via IMP in both Outlook Classic and Thunderbird.

  * Outlook Classic (.sot files): Taking up 16 GB of disk space.
  * Thunderbird: Taking up just 2.1 GB of disk space.


The reason Thunderbird is running so lean and fast for me is due to a 
few specific optimizations I made to keep the database small and make 
the interface incredibly responsive with JAWS and NEDA. If anyone is 
looking for an alternative to the Outlook transition madness, here is 
the exact blueprint of what I did:

Okay, *blushing*. Confession time. I had Gemini help me write this email 
and I am gasping at the Commander Data style above sentence, so let me 
say this in my own words.
The reason Thunderbird is running so nice for me and taking up so little 
disk space is due to a few changes I made with some caveats to keep in mind.

1. Unsubscribed from the "All Mail" Folder: Gail’s IMP implementation 
causes "All Mail" to act as a massive duplicate of your Inbox and Sent 
items. Unsubscribing from it cuts the background sync and database size 
in half. Of course, if you are always going into this folder, then you 
won't want to unsubscribe from it. Note that by unsubscribing from it, 
you will not break anything, and you can still access this folder from 
the web interface, which is completely accessible.
2. Disabled Duplicate Sent/Archive Storage: In Copies and Folders, I 
unchecked "Place a copy in" for Sent messages and disabled archiving. 
Because Gail natively saves a copy of sent items on the server, letting 
Thunderbird do it too just creates sync lag and extra clutter. Note that 
you should have also done this in your Outlook configuration. I promise, 
it will work just fine.
3. Turned Off Local Message Caching: In Synchronization & Storage, I 
disabled "Keep messages for this account on this computer." Thunderbird 
now pulls message bodies on the fly, which completely stops the app from 
grinding the CPU and filling the hard drive with hundreds of thousands 
of files. In other words, each message is now downloaded as I open it. 
Because I have a fast Internet connection, this small lag is slightly 
noticeable but not a time waster for me and it's an acceptable thing to 
deal with for a lot smaller space.
4. Personalized Notifications: In General Settings, I turned off the 
Start Page. For new messages, I disabled the visual alert banners and 
system tray icon changes, leaving only "Play a sound." This keeps the 
system focus clean. Note that you can do similar in Outlook so it only 
plays a sound without popping up an alert that your screen reader reads, 
unless you want that of course.
5. Screen Reader Friendly Window Management: In General Settings, I 
changed the option to open messages in a "New message window" instead of 
a new tab. This is a huge win for screen reader navigation because it 
allows you to instantly close a read email using the Escape key, 
dropping you right back into your message list. If you open a message in 
a new tab, you will need to press CTR+W to close the email, and while 
I'm personally okay with that, I find that using the Escape key is great 
for those users who are transitioning from Outlook to Thunderbird.
6. Automated Maintenance: Under Disk Space, I set it to automatically 
compact all folders if it will save more than 250 MB. (Remember, 
deleting an email in Thunderbird only hides it until you compact the 
folder to purge it).
7. Disabled Hardware Acceleration: Turning this off under General 
Settings often removes hidden interface lag and focus issues when 
working with screen readers. Some people say this is an old-school 
setting to turn off, and it may or may not make a difference, but I do 
it anyway.
8. Disabled Attachment Keywords: In Composition, I turned off the 
attachment reminder feature so it stops scanning my text and prompting 
me to attach a file based on words I typed. This doesn't change the 
performance of Thunderbird, but it's something that I prefer greatly.

As far as add-nos go, the one I absolutely rely on the most is 
Nostalgia++. It makes keyboard navigation, moving messages, and folder 
management incredibly efficient. I also use a duplicate message remover 
to keep things clean.

I don't necessarily hate Outlook, but with the uncertainty around the 
"New Outlook" transition, Thunderbird has become a incredibly viable, 
lightning-fast, and lightweight alternative once it's customized properly.
*OMG Gasp* There goes Commander Data again. Here is what I really meant 
to say.
I don't hate Outlook at all, but I also don't think it's the end-all of 
email programs. Unless you absolutely need it for work, there is no 
reason you can't look at other methods for email. I also agree that the 
new Outlook is perfectly accessible and I think it's important for 
people to start using it if they don't want to have a cold turkey 
experience when and if Classic Outlook goes away. If you don't want to 
learn the New Outlook, then consider webmail, like the mail.com website, 
or consider Thunderbird, which has been around for more than 20 years 
and is very stable. I also confess that I am very much gmail biased. 
While I think that the Outlook.com and the Yahoo.com email web 
interfaces are accessible, I find that the Gmail.com web interface is 
nicer to use. Oh, and if you switch to another email program or do 
webmail, you may need to get used to pressing CTRL+Enter to send the 
email. This is a huge change for those who are used to ALT+S in Outlook, 
which will allow you to also press CTRL+Enter to send email.

--
Raul Gallegos
Access Technology Trainer, RGA Tech Solutions
www.rgats.com
Phone: (832) 639-4477
Direct Email: Raul.Gallegos at rgats.com
Team Inbox: training at rgats.com
“Learning is experience. Everything else is just information.” — Albert 
Einstein


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