Forum der Gemeinschaft Alle Produkte

This seems to have occurred in the last month or so.

Whenever I click on a message in the folders pane, the message is not displayed correctly in any of the three layout views but, if I am offered to display in a browser, it does! Also, if I select 'Edit as a new message' it displays correctly, as also do iPhone and iPads. The screenshot shows the problem?

Any ideas, anyone?

It's very odd. Normally moving an email, say from the Inbox to the relevant year's archive, takes "no time at all".

Which is true for all the mailboxes shown on the attached screenshot, EXCEPT for the four at the bottom. Moving even one message from Inbox to Yiddish can take ten seconds or longer (with the dreaded "Not Responding" occasionally). Moving something in the opposite direction is also screwy, only from those four.

I had thought that it was because they're rather large. This first started when there were just Yiddish and MSW, and I split off most of the earlier years into the archives shown. To no avail.

It's only an annoyance, but I'm puzzled about how such a thing could happen.

Also very slow tagging or untagging a message just in those mailboxes.

Moderator Notes:

• need a performance profile https://support.mozilla.org/en-US/kb/profiling-thunderbird-performance

Thunderbird (153.4.0esr (64-bit) ) does not display or let the user change its printer setting before launching print preview from the print command. If Thunderbird is set to choose a missing printer, it gets stuck trying to contact the missing device in order to prepare a print preview. It seems to be stuck forever, it does not seem to time out. There is no cancel button. If you close the document tab, you can permanently lose the document if it is a draft email, unless the email service saves it in a trash folder. The printer setting can be cleared if the user manages to learn how to display and clear the troubleshooting information.

Thunderbird needs to display the printer setting and permit the user to change it before launching the print preview operation. It needs to display a cancel button during the print preview operation.

I upgraded my system to Kubuntu 26.04 LTS and started Thunderbird. The window where messages are listed was covered with Thundrbird presentation asking for donation. Only edge of one message is seen above the presentation and I cannot get to the list

Lately, Thunderbird has been using excessive CPU time even when idle. I am on Windows 11 and running the 153.3.1esr release of Thunderbird. It's impacting other applications. When I exit Thunderbird, everything runs faster. Right now it's using over 7% CPU and about 500 MB of ram.

Hardware is HP Pavilion Desktop 590-p0xxx. Intel i5-8400 2.8 GHz 12 GB ram.

Hi,

I'm having a performance issue with Firefox on my computer. After Firefox has been running for a while, it sometimes becomes noticeably slower when I use several browser-based tools and keep multiple tabs open.

For example, I noticed it while using an online one rep max calculator to work out estimated lifting numbers. The calculator itself is fairly simple, but Firefox occasionally starts using more CPU and the browser feels less responsive.

I have several extensions installed, so I'm not sure whether an extension, a particular tab, or Firefox itself is responsible.

I've already tried closing unnecessary tabs, but the problem can still come back.

Is there a good way to determine whether a Firefox extension is causing the high CPU usage? Would checking about:processes or running Firefox in Troubleshoot Mode be the best way to narrow it down?

I'm especially interested in knowing how to identify the specific extension or tab responsible rather than disabling everything permanently.

Thanks.

Hello, so. I just moved from Chrome to Firefox recently. My first move was on my laptop which I enjoyed the experience so I had to try out the mobile version. So far the experience has been pretty okay but I have been coming across occasional crashes and the app is sometimes slow generally. I tried figuring out what's going on by googling how to make the app run faster. I deleted all my mobile extensions but the difference wasn't too visible. I still do experience some last when accessing memory hungry website's like Instagram and Facebook. I know I can just have the apps but I prefer to use the website's (it helps me reduce my doom scroll period). But if I'm being fully honest, I think it's because of my phone in general. My phone is a Samsung A16. The phone on it's own has been generally slow so I think that might be the case but I can't say for sure because the frequency of the app freezes and lack in speed wasn't as common when I was using Chrome. By no way am I saying Chrome is better but I'm just saying that Chrome was faster than Firefox. I'm mostly facing these problems on my phone. Who knows maybe it's my phone still getting used to the app. I really want Firefox to work because it's been a good experience overally plus the added privacy and VPN are a great bonus I never knew I needed till now. Anyways I hope this is just my phone being moody and not the app, I am planning on upgrading the phone soon anyways so I hope that will change. But yeah I just wanted to let you know that this is what I'm experiencing, otherwise everything else has been great. I hope someone can help me out.

Have a great day.

I’m trying to import my email accounts from Thunderbird on Linux into Thunderbird for Android 23.0. On my Google Pixel, tapping “Scan QR code” briefly highlights the button, but nothing else happens. The camera view never opens and no error appears.

Camera permission is granted. Thunderbird is up to date, and force-stopping and restarting the app did not help. Has anyone encountered this or found a workaround?

My Thunderbird app takes some minutes to start up. Updates are OK, troubleshooting does not show any failures. Emailing functions well, no problems. There is a new problem: dragging files to my Explorer has stopped to function.

I have a good HPPro "Desc 400 G5 MT"" PC running on Windows 11 (no problems).

Kindly advice actions to take. Do I loose my Address Book in case I uninstall my Thunderbird and Install a new copy of the Programme. Yours - Jarl Jaatinen, Finland

Hello David and thank you for your prompt answer. The situation between my mails ubfortunately remain the same. Nothwithstanding my re-installation of Thunderbird. I run a "HP ProDesk 200 GS MT" PC with Windows 11 and full virus protection etc. I clean my PC and run troubleshooting regularly. Never any problem. And now: Thunderbird opens at command and can be moved on my screen with minutes of delay. I can select mail address book and calender but I can not use them. Incoming ermails show on the screen but I can noy open them. If a drag an incoming mail to my Explorer app, then Explorer gets blocked and I must restart my PC. I can not open the Send Mail function. I can not open older mails on the Expolrer. Thus I am completedly stuck. Can you fix this problem? In case you can not assist me, I will load the Outlook program to get going. Pleas send tour commenst ASAP. Yours Jarl Jaatinen, Finland

I'm on a 15" MacBook Air M5 running and updated OS to Golden Gate 27.0 a couple of days ago. when I Open Thunderbird the emails are up but page is blank, just spinning pizza wheel. I've force quit Thunderbird and restarted and force quit and shut down several times but ends up with the same result... just the spinning wheel. Any suggestions ?

I'm running Thunderbird 156.0 on Windows 11 with ten IMAP accounts (Gmail, Outlook.com and Zoho) plus one Exchange account served by the Owl add-on, and until recently about 30 GB of mail held locally. On starting Thunderbird, folders are destroyed and re-created empty. It happens often, but not every time. The summary files are deleted, and in some cases the whole folder directory goes with its mbox message store inside it. The folders then come back in the folder pane holding nothing, and Thunderbird downloads all the mail again over several hours, re-indexing as it goes. When a folder directory has been re-created, it appears on disk with a numeric suffix, so one of my folders now lives at COMPLIANCE-1.sbd with an abandoned COMPLIANCE-2.sbd sitting beside it. Column layouts and favourite-folder flags are lost at the same time, because they live in the summary files. It happens on ordinary restarts, rather than after Windows updates or sleep.

Those orphaned directories have let me date three separate occurrences: 18 August 2025, 19 February 2026 and 19 September 2026 — those being the occasions that happened to leave orphaned directories behind. Most leave no trace, because the folder refills and the evidence is overwritten. Each has the same signature. A folder directory is created, and roughly five minutes later a summary file of about 1,200 to 1,500 bytes, which is an empty summary, is written into it. In the two older cases it was never touched again. In one event eleven summary files across two folder trees were written with an identical timestamp to the second, so it appears to be a single operation across a set of folders rather than something that walks through them one at a time. One of the destroyed folders left its mbox stores behind, orphaned with no summary file, while another was deleted whole with 50 MB of mail inside it, so there seem to be two different outcomes in the same event. Bitdefender is running, but its quarantine holds nothing from the September event, and there are no Thunderbird entries in the Windows event log for that period.

The part that may be useful is that I have reproduced it. On 19 September I renamed folderCache.json aside with Thunderbird closed and restarted. Eight minutes later folders were destroyed. The twelve I could identify were all children of INBOX, across two different mail providers, though other folders elsewhere were emptied in the same minute. The Exchange account served by the Owl add-on was untouched. At the moment of destruction the Activity Manager showed "[NONEXISTENT] Invalid folder: INBOX^Practice Filing (Failure)" on the Gmail account, where the correct hierarchy delimiter is a forward slash rather than a caret. My folderCache.json is 5.2 MB with about 13,000 entries, of which roughly 1,200 point at summary files that no longer exist and 9,600 sit under an obsolete lowercase profile path from the 129 to 139 version window. I would rather not delete it again given what happened, so I'm looking for any idea of what triggers this on an ordinary restart, and whether there is anything I can set that would stop Thunderbird discarding local folders when it decides they are missing.

I am going in circles with this. If I build a new profile, is there any point bringing the old configuration across, or would that just reimport whatever is wrong? I assume the address books and filter files are safe and that folderCache.json, prefs.js and the unified-folders directories are not, but I do not know whether the problem lives in the profile at all, or in how Thunderbird handles an account set this size.

Any ideas?

For a few days I'm having trouble with Asana mails (notification mails informing me about replies, comments, etc).

Clicking on the mail to view it freezes Thunderbird for a good 5 seconds while one CPU core spins at 100%. This only happens with Asana mails (or at least I haven't found any other problematic senders).

I guess it's a problem with validation or parsing of the mail's HTML content. But I don't know how to debug this.

I can't pinpoint exactly when it started happening, but it was around the time I've switched to the [new snap release track](https://support.mozilla.org/en-US/kb/channel-choices-thunderbird-snap-and-flatpak#w_snap-channel-changes-in-2026). But since this happens with Snap and Flatpak I think the culprit may be the 153.0 update.

Things I've tried:

• Clearing cache and msf files.
• Troubleshooting mode with add-ons disabled.
• Reinstallation. Creating new profile + importing old data.
• Switching from Snap to Flatpak
• Switching Message Body display to Plan Text or Simple HTML.
• Disabling HW acceleration.
• Checking console for suspicious output.

Anything I can do to create handle the problem or collect information for a proper bug report?

After reading and deleting emails the email list will just go blank for a bit of time, sometimes I need to exit clear cache and reopen for the list to display. This happens in both the beta and the none beta versions

I have a completely vanilla install of TB fully up to date as of this writing [it is version = 156.0.1 (aarch64) and I checked for updates], no extensions, no proxy, on a new OSX 27.0 (Golden Gate) computer and even when idling it is using substantial resources. The only thing even remotely non-basic is their is the Proton Mail Bridge to connect to Proton Mail for one of the linked email accounts, but that is its own little program with its own threads and takes almost no system resources even when sending or receiving mail (which is not happening currently.) Look at the attached screen shot.

In the screen shot I have left Thunderbird to idle for about an hour. No new mail in that time and other then clicking on or off the window to bring it to the fore I have not interacted with the program at all myself. Meanwhile Thunderbird and its Thunderbird GPU Helper are using substantial amounts of the CPU and GPU, have a combine total of 86 threads (more then any two other things running except the kernal tasks) and are hogging ram (not depicted).

Meanwhile among a few other applications (Apple Music, OfficeLibre, etc...) I also have Brave Browser opened in the background running with two windows and a total of 8 tabs wherein Brave is actively downloading GB of data from MEGA as well as performing other admittedly lighter tasks. Even when doing all this, Brave barely registers on computer resources compared to Thunderbird and Thunderbird GPU Helper when they are just idling.

Is this all proton mail's fault with the Proton Mail Bridge? If not is there anything I can do to quell the hunger for computer resources of this voracious beast of an email client that is TB and uses resources as if it were a video game even when idling?

My Thunderbird connected to my gmail is running slow. Thunderbird is not running slow on my other (non-gmail) account. It takes 10-15 seconds for an e-mail (from gmail) to be deleted or moved within Thunderbird. I have tried "compacting folders" and "repairing folders" and that does not help. Please help!

Hello Firefox Support,

I would like to report a reproducible video playback problem in Firefox on Windows 11. I have already spent considerable time troubleshooting it, including testing Firefox graphics and video related settings and ultimately performing a completely clean reinstall of Firefox. The problem persists after the clean installation.

My system configuration is: Device name: Mephisto PC Operating system: Windows 11 Pro for Workstations, 64 bit Windows version: 25H2 OS build: 26200.9457 Windows Feature Experience Pack: 1000.26100.360.0 Processor: AMD Ryzen 7 9700X 8 Core Processor, 3.80 GHz Installed RAM: 32.0 GB, 31.1 GB usable Graphics card: AMD Radeon RX 7800 XT, 16 GB VRAM Integrated graphics: AMD Radeon(TM) Graphics, 486 MB System type: 64 bit operating system, x64 based processor The primary discrete GPU used by the system is the AMD Radeon RX 7800 XT

The problem appeared suddenly. Firefox had been playing videos normally the previous day. As far as I am aware, neither Firefox nor the AMD graphics driver had been updated immediately before the problem appeared.

The symptom is severe video stuttering during playback in Firefox. The video is not merely dropping an occasional frame. Playback becomes visibly and consistently jerky rather than smooth. The most important finding is that I have been able to isolate the problem specifically to Firefox's hardware video decoding.

In about:config, I changed: media.hardware-video-decoding.enabled from: true to: false With hardware video decoding disabled, video playback immediately becomes smooth and continuous. If hardware video decoding is enabled again, the stuttering returns. This is currently the only workaround I have found that reliably eliminates the problem.

I also tested Firefox's DirectComposition hardware video overlay setting: gfx.webrender.dcomp-video-hw-overlay-win Setting this to false did NOT solve the problem. Video playback continued to stutter.

I investigated the related DirectComposition/WebRender video overlay preferences as part of the troubleshooting process as well, but disabling the hardware video overlay did not reproduce the improvement obtained by disabling hardware video decoding itself.

I then decided to rule out corruption of the Firefox installation or profile. I performed a complete, clean Firefox reinstallation. After reinstalling Firefox from scratch, the exact same problem remains. Therefore, the behaviour is reproducible on a clean Firefox installation.

The important observations can be summarized as follows: Firefox with hardware video decoding enabled: video stutters severely. Firefox with media.hardware-video-decoding.enabled = false: video playback is smooth. Firefox with gfx.webrender.dcomp-video-hw-overlay-win = false: video still stutters. Completely clean Firefox reinstall: problem still occurs.

The PC itself has not changed hardware, and the problem appeared despite Firefox having worked correctly on the same machine previously.

Given these results, this appears to involve Firefox's hardware accelerated video decoding path and its interaction with the AMD Radeon RX 7800 XT, the AMD graphics driver, Windows 11 video acceleration, or some combination of these components, rather than ordinary Firefox profile corruption.

Disabling hardware video decoding is a functional workaround, but I do not consider it an ideal permanent solution on a modern GPU which is specifically designed to provide hardware accelerated video decoding. I would therefore appreciate assistance in determining why Firefox's hardware video decoder has suddenly begun producing severe stuttering on this system.

If useful for diagnosis, I can provide additional technical information from about:support, including Graphics, Media, WebRender, hardware video decoding, codec and driver information. I can also perform specific diagnostic tests if you tell me exactly what information is required.

Thank you.