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Lately, when I try to click on a different mailbox or message , nothing happens. repeating clicks sometimes works, and sometimes i have to first click on what I was previous viewing to get what I want to highlight, or click on different areas of a message or mailbox to get it to work. I am on mac tahoe 26.2. Did not have this problem before. What can I do to fix this problem?

Thanks Dan

The Inbox on my Thunderbird emails shows 224 messages but do not open. I have tried opening and deleting but to no avail.

IMPORTANTLY I am still receiving new emails.

Thunderbird has become crazy slow. 5-10 minutes to display an email. It's not my email server because my phone connects to and displays email fast. I have been through all the advice that I can find and cleared, checked, disabled everything that might slow it down. Still crazy slow. If I kill it and restart, I get about 3-4 minutes of reasonable performance and then it just stops. Latest Release Version V147.0.1.

i have a fast machine with 32Gb memory only 60% used, everything else runs fast

I don't want to junk Thunderbird, but it's unusable.

Help!

I posted this question some time back but didn't receive any helpful answers and don't know where my post is. In the upper right-hand corner there is suppose to be 3 symbols. One to lower the app, one to make the app full screen or partial and one with an X. I have jumbled symbols where the 3 good ones are. It does it in trouble shoot mode. I tried disabling addons but I can't get the normal symbols back. Here's what it looks like... Thank you for any help.

For a few days now, synchronization and opening new messages from a Gmail account configured in Thunderbird have been very slow. I use Thunderbird 140.x, which is regularly updated, and the mailbox has been configured for at least 5 years. Only in the last week has the problem emerged, rendering it unusable. Timeout errors and opening a new message after 2-3 minutes. I've cleared the cache, the database, and re-indexed, but nothing has changed. I've deleted and reconfigured my Gmail account, but nothing has changed. My Gmail mailbox is about 45 GB (I've seen much larger ones without losing performance). I tried installing Thunderbird on a new, clean PC, but the same thing. Extremely slow. Google support hasn't found any issues. Do you have any other suggestions for getting Thunderbird back up and running? Thanks.

My file named "Archive" (no extension) in the ImapMail\outlook.office365.com\ folder is now 3 GB. I like all my inbox email progressively be archived in a single archive folder, searches are easier (in do not need to tick off "search subfolders" when I do Edit -> Find -> Search and I select the Archive folder. But I was wondering: does this affect speed (speed at which chunk of emails are archived at once, search speed etc) ? Should I archive by year? If it makes a big difference, how do I get thunderbird to get everything moved in years folder? If I select "yearly archived folder" in the attached screenshot, is it gonna start archiving by year from now on but it leaves the old files in a single folder, or does it creates also the yearly older folders and split all the past emails on those folders?

Some websites won't load at all while other are very slow to load but some will load just fine, example Crunchyroll (screenshot attached) won't load at all its just spinning loading icon and a white page but if I try it in a different browser it works just fine, but with Youtube it will load but is choppy and low quality videos and same thing as before I load it in a different browser and no problems. I have tried every possible solution I can find from clearing cookies and cache to refreshing Firefox even scanned for malware and virus nothing has worked please help me figure out what is happening and why it's only with Firefox that I am having this problem and its not hardware can play online just fine and download games from steam perfectly fine.

Hello,

same issue as described here: https://support.mozilla.org/mk/questions/1487230 I use: 144.0.1 (aarch64) on macOS 26.0.1 (25A362) (MB Pro M1 Pro).

1. I've drafted an email, then hit save / closed the email and opted to "save changes". 2. I try to edit that email, but it is just "flashing" in the preview screen. I right click on it to "edit draft message", but that just brings up a blank email. 3. The status in the bottom left of the screen shows "loading message..." "downloading message", repeatedly. 4. It was working fine earlier in the week, but Thunderbird Desktop Version 140.7.0esr | Released January 13, 2026, seems to be when the problem started?

First time using Thunderbird 143.0 (64-bit) on MacOS Sequoia 15.6.1. System is a MacBook pro 2.4 GHz 8-Core Intel Core i9 with 64 GB 2667 MHz DDR4.

Installed Thunderbird. Added a fastmail.fm and icloud.com account. Fastmail account is 14GB account. icloud is 50MB.

System is continually pausing during use and the mouse turns into the rainbow spinner. Application recovers after a second or two but it's annoying that it happens.

Thunderbird ActivityManager shows that indexing is not in progress. MacOS ActivityManager shows that CPU for Thunderbird going up to 100% during these periods.

Aside from the pauses, Thunderbird is stable and does not crash.

I run Thunderbird 128.12.0esr 64bit on Linux Mint 21.3 Cinnamon.

Ever since I updated to this version 128.12.0esr, T-bird email manager has become almost useless. Constant freezing, constant repopulating at times and of course freezing. Including changing my folder configurations.

Every time I access the calendar it locks up my system. uses 5gb memory and 5% of CPU Freezing & Slowing the system. Often I have to close it to regain control over the rest of my programs.

I have a 32gb RAM, 12th Gen Intel© Core™ i9-12900HK × 14,

Each time open T-bird i am not always able to access one of my 5 email accounts. I have been using T-bird for over 10yrs so I have gone through some up/downs, but nothing like this before.

"It's so bad that I am trying out Evolution to see if I can switch."

I shouldn't ever have any issues with any programs, especially on Linux based on my systems capabilities.

I see a lot of people are having issues with this version and nobody seems to be fixing the problems.

I need some actionable FIXES or to know this issue is being taken seriously before I abandon T-bird and try out something else. I'd like to have a functional T-bird.

Thank you

Will this fricking "The bookmarks and history system will not be functional" B.S. ever be fixed? Firefox didn't have this issue for years now for almost a year every time Firefox starts up on a cold boot I get this idiotic non-sense message!. I have to close the browser I JUST OPENED and reopen in. This error is pure B.S. as again cold boot, just launched there is NOTHING other than Firefox that might be accessing the various sql.db's...so if this message is to be believed Firefox is blocking Firefox from Firefox... FIX THIS!

What minimum memory spec is recommended for current Firefox usage? Have new computer with 16GB memory, 512 storage, intel core Ultra 5-225 processor & windows 11. Have not set it up yet.

This has been consistent for over a week now. One folder brings TB to a halt if I try to open any message in it. I have many folders and many I rarely open so I can't be sure it's just this folder but certainly all other folders seem fine and fast. This particular folder did have many messages in it but I deleted them all, accepting that I didn't really need them. I then repaired the folder but was a bit shocked to find the problem continues. The folder says it is 20.9Mb and that it contains three messages each of 7Mb. That's plausible as it just gets one Email per day from my server with some information. The size can vary quite a lot. I could just delete the folder and recreate one with the same filter rules, or I could delete the filter rules before doing that, or ... what?! Technical is that it is TB 140.3.1esr running on a fairly powerful Kubutu machine with 64Gb and really nowhere near any resource limits. It's pulling messages from the one IMAP server and, as I say, everything else seems fine. Any thoughts welcome, TIA, Chris

In a thread discussion about the flag, "browser.tabs.unloadOnLowMemory" dated 23-Nov-2022 (https://news.ycombinator.com/item?id=33706117) it was mentioned that we've disabled tab unloading on Linux because low-memory detection just didn't work.

Has the issue been fixed? Does the low-memory detection work in Linux? Can it be enabled now?

Does it get triggered when SWAP is being used? Or when system free RAM falls say to about 25% of total physical RAM?

Hi. I access a gmail account via Thunderbird. It's generally quite efficient, but recently it has become very sluggish. I have pretty fast internet, wired at 1G, so usually my mail appears almost immediately. In the last week or so it has slowed down dramatically, sometimes requiring multiple login attempts. Any idea what's going on? Thanks. Steve

I opened a new Firefox session (closed the previous one properly using the “Exit” option, without force-killing it) and had only 4 tabs open:

One YouTube video at 1080p One bookmaker site that may have a 240p video playing Two Flashscore tabs (static pages, no video)

When I end all firefox.exe processes, the Task Manager shows that about 10 GB of RAM is freed.

How can just four tabs be using that much memory? Please help me with this issue.

Thank you!