Thunderbird is already running, but is not responding. To open a new window, you must first close the existing Thunderbird process, or restart your system. Error received when clicking a mailto link in firefox.

User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101206 Ubuntu/10.04 (lucid) Firefox/3.6.13
Build Identifier: 3.1.7+build3+nobinonly-0ubuntu0.10.04.1

Binary package hint: thunderbird

This thunderbird error is given when clicking a mailto link. Instead of using the thunderbird that's already open it tries to open a new instance. Preferred Applications has Thunderbird select, but I have also tried Custom command "thunderbird %s". This has been tested on 10.04 and 10.10. Both result in this error if thunderbird is already running.

Thunderbird is already running, but is not responding. To open a new window, you must first close the existing Thunderbird process, or restart your system.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: thunderbird 3.1.7+build3+nobinonly-0ubuntu0.10.10.1
ProcVersionSignature: Ubuntu 2.6.35-25.44-generic 2.6.35.10
Uname: Linux 2.6.35-25-generic i686
Architecture: i386
Date: Tue Feb 1 10:19:09 2011
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
ProcEnviron:
 LANG=en_CA.utf8
 SHELL=/bin/bash
SourcePackage: thunderbird

Reproducible: Always

Steps to Reproduce:
1. Click mailto link in firefox
Actual Results:
Error appears

Expected Results:
New mail window

Do you launch Thunderbird with the noremote option ?

I do not use "-no-remote" option when starting Thunderbird. The command I usually use to start up Thunderbird is "thunderbird %u". On Ubuntu "System > Preferences > Preferred Applications" sets mailto: to run the command thunderbird %s.

Name: Thunderbird
Version: 7.0
User Agent: Mozilla/5.0 (X11; Linux i686; rv:7.0) Gecko/20110916 Thunderbird/7.0
Application Build ID: 20110916152645

I've tried both launching thunderbird with --no-remote and without it. Both give me the same error as Comment#0.

I have to quit TB to click on a mailto link. I usually just copy/paste :(

So is this a regression ?

I can confirm this bug with tb 17.0.2+build1-0ubuntu0.12.10.1

Not sure when it started happening (after upgrade from 16? due to some extension installation / activation?), but I can never close tbird any more. a "killall thunderbird" does the trick.

Erm. Please ignore that (and feel free to close this bug if you like). I tried starting in safe mode to see if it was one of the extensions, and the next normal start onwards (both from the kde launcher and the command line) it exits normally every time. No clue what happened.

I'm hit by this bug all of a sudden (after years of no issues).

Thunderbird 38.3, Windows 8.1 x64 ... happens when clicking mailto: links in both Firefox and Chrome.

Safe mode with all add-ons disabled does not fix it.

I started TB normally (not using --no-remote)

I'm running Debian Jessie and I seem to have the problem as well.

First, I have two main Firefox profiles, "default" and "empty". Empty has few extensions while default is my fully loaded profile. In order to be able to easily run them, I create custom .desktop files that execute "firefox -P <default|empty> -new-instance %U" If I don't use the "-new-instance" (or "-no-remote"), and I decided I want to run the empty profile but the default is already running or vice versa, I get the "already running error".

It seems, when I create a shell script to execute "xterm" and set it as the mail application in Firefox, I get a bunch of MOZ_ environment variables. I played around with un-setting the variables before running Thunderbird. It just so happens that, at least for me, if I unset a variable "MOZ_NEW_INSTANCE" then it seems to work. To verify I start Thunderbird and then open a terminal without any MOZ_VARIABLES and execute "thunderbird mailto:<email address hidden>". Everything works. If I then execute "MOZ_NEW_INSTANCE=1 thunderbird mailto:<email address hidden>" I get the "already running" error.

So it seems that what is happening, at least for me, is when I run Firefox with -new-instance, it sets an environment variable that is in turn passed to child processes. When I click on an email link it launches Thunderbird, but that environment variable is set and Thunderbird tries to start a new instance. The same seems to happen if I use -no-remote instead, it just sets a variable MOZ_NO_REMOTE=1

I create the following script and set it as the mail handler for the time being.

    #!/bin/sh
    env -u MOZ_NEW_INSTANCE -u MOZ_NO_REMOTE thunderbird "$@"

Currently there is no way around "-no-remote" or "-new-instance" with Firefox it seems. If I launch one profile, and wish to launch another profile, then it will complain unless I use one or the other. Ideally, there should be a way to launch multiple profiles, but to have "remote" features with both, either designating one as the default to receive remote commands or a chooser to list available instances to receive remote commands. For now, the shell script to remove the environment variables seems to help.

Is this really linux only? (not according to comment 7)

(In reply to Wayne Mery (:wsmwk) from comment #9)
> Is this really linux only? (not according to comment 7)

I can confirm this also occurs on Windows (10) with Thunderbird 60.8.0 (without -no-remote) when running Firefox with -no-remote (to use two Firefox profiles simultaneously).

Martin beat me to it.

Seems to be a cross platform problem, and I can confirm that it happens when using -no-remote on Win10 and Pop_OS! 19.04 on TB 60.8

Could the issue really be in Firefox as it is the common denominator?

(In reply to Brian Vanderburg from comment #8)
> I create custom .desktop files that execute
> "firefox -P <default|empty> -new-instance %U"

I don't create custom .desktop file with `-new-instance` for FF but still get the "already running error" when trying to open "mailto:" links while TB is open.
How is that?

- If I run it with `firefox` command, which is a script, I get the "already running error" on `mailto:` links problem
- If I run it with `/usr/lib64/firefox/firefox`, which is a binary - no problem

I have no idea whether some of the old, old comments in this bug report are still relevant or not, but there was no mailto problem between Firefox and Thunderbird in Fedora 29, or any earlier Fedora release in recent years that I can recall. I first saw this symptom in Fedora 31, which currently has Firefox 75.0 (64-bit) and Thunderbird 68.7 (64-bit). It does not occur when Chrome is the browser and Thunderbird the default email client.

It is unclear whether the recent visibility of this symlptom is caused by underlying changes in Fedora 31, Thunderbird, or Firefox, but since the error only occurs when both Firefox and Thunderbird are involved, that points the finger at one or both of those applications. From the users viewpoint, these are two independent applications. Whatever status information or internal support that Firefox and Thunderbird are sharing that causes this problem, they obviously shouldn't be sharing. It should be irrelevant to Firefox's external behavior whether Thunderbird is the default email client, and irrelevant to Thunderbird external behavior whether it receives a mailto request from Firefox or some other browser.

This defect is a major annoyance, as I frequently use web sites with mailto links, and Firefox and Thunderbird are my preferred applications for browsing and email.

I had no problem like this until Ubuntu 21.04 (which I upgraded to lately).
Clicking on mailto-links in Firefox result in the error message by Thunderbird "TB already running..."
I have FF 88.0 and TB 78.8.1 - system is 64 Bit.
I recently had a problem (since the aforementioned upgrade) with Firefox not able to open tabs or windows when clicking on a link in an email (in TB), but today it was gone. Maybe as a result of an update I received yesterday?

I hav a question on this case. Why does this "Already running" dialog even exist?

In my opinion Thunderbird should all time automatic open the existing application. I do not know any other application with this nonsense Dialogs. What user would be interested in such a detail if the app already run or not. In all cases a normal user inter act with thunderbird I personally know no situation where this error shows a good information.
 * If the Thunderbird app already run do something in thunderbird.
 * If thunderbird do not run start it and than do something in tunderbird.
 * If there is a case that Thunderbird do not react on a call say something like:
  "Thunderbird do not answer. Should I kill it and start a new one. If you wish check yourself leaf this dialog open. It will disappear the moment thunderbird do answer."

Similar reports https://mzl.la/3J81rqF

I have this problem in Ubuntu 22.04.1 LTS with Thunderbird 91.11.0 and am shocked to see that this bug has persisted for 12 years.

*** Bug 1796588 has been marked as a duplicate of this bug. ***

Same problem here on Fedora. Please let me know when this is fixed

I reported first seeing this problem three years ago after upgrading to Fedora 31 with Firefox 75.0 and Thunderbird 68.7; but at some point, for sure by Fedora 35, the problem for me had disappeared. I just assumed they had fixed it, either intentionally are as a side effect of some other change.

I'm currently on Fedora 37 with Firefox 109.0.0 and Thunderbird 102.7.1 and haven't seen the problem re-occur after installing Fedora 35. If you are on Fedora 35 or later and seeing this problem, it has to be something perhaps unique to your system, like some combination of configuration or account settings, or a timing issue that is affected by hardware speed, etc. It definitely doesn't affect all users of Fedora, which makes it a difficult to fix if the conditions to make it occur on other systems are unknown.

I can confirm the same bug, using Librewolf Flatpak and clicking on a mailto link.

Thunderbird latest Flatpak from Flathub

--- Software ---
OS: Fedora Linux 38.20230814.0 (Kinoite)
KDE Plasma: 5.27.6
KDE Frameworks: 5.108.0
Qt: 5.15.10
Kernel: 6.4.10-200.fc38.x86_64
Compositor: wayland

(In reply to Mannshoch from comment #16)
> I hav a question on this case. Why does this "Already running" dialog even exist?
>
> In my opinion Thunderbird should all time automatic open the existing application. I do not know any other application with this nonsense Dialogs. What user would be interested in such a detail if the app already run or not. In all cases a normal user inter act with thunderbird I personally know no situation where this error shows a good information.
> * If the Thunderbird app already run do something in thunderbird.
> * If thunderbird do not run start it and than do something in tunderbird.
> * If there is a case that Thunderbird do not react on a call say something like:
> "Thunderbird do not answer. Should I kill it and start a new one. If you wish check yourself leaf this dialog open. It will disappear the moment thunderbird do answer."

Firefox has the same dialog, but normally only when its not responding. Thunderbird is the only app that has this dialog and I agree its totally useless as its not meant to be ran with multiple windows (even though possible, for example "thunderbird -p")

(In reply to Brian Vanderburg from comment #8)
> I'm running Debian Jessie and I seem to have the problem as well.
>
> First, I have two main Firefox profiles, "default" and "empty". Empty has
> few extensions while default is my fully loaded profile. In order to be
> able to easily run them, I create custom .desktop files that execute
> "firefox -P <default|empty> -new-instance %U" If I don't use the
> "-new-instance" (or "-no-remote"), and I decided I want to run the empty
> profile but the default is already running or vice versa, I get the "already
> running error".
>
> It seems, when I create a shell script to execute "xterm" and set it as the
> mail application in Firefox, I get a bunch of MOZ_ environment variables. I
> played around with un-setting the variables before running Thunderbird. It
> just so happens that, at least for me, if I unset a variable
> "MOZ_NEW_INSTANCE" then it seems to work. To verify I start Thunderbird and
> then open a terminal without any MOZ_VARIABLES and execute "thunderbird
> mailto:<email address hidden>". Everything works. If I then execute
> "MOZ_NEW_INSTANCE=1 thunderbird mailto:<email address hidden>" I get the "already
> running" error.
>
> So it seems that what is happening, at least for me, is when I run Firefox
> with -new-instance, it sets an environment variable that is in turn passed
> to child processes. When I click on an email link it launches Thunderbird,
> but that environment variable is set and Thunderbird tries to start a new
> instance. The same seems to happen if I use -no-remote instead, it just
> sets a variable MOZ_NO_REMOTE=1
>
> I create the following script and set it as the mail handler for the time
> being.
>
> #!/bin/sh
> env -u MOZ_NEW_INSTANCE -u MOZ_NO_REMOTE thunderbird "$@"
>
> Currently there is no way around "-no-remote" or "-new-instance" with
> Firefox it seems. If I launch one profile, and wish to launch another
> profile, then it will complain unless I use one or the other. Ideally,
> there should be a way to launch multiple profiles, but to have "remote"
> features with both, either designating one as the default to receive remote
> commands or a chooser to list available instances to receive remote
> commands. For now, the shell script to remove the environment variables
> seems to help.

This is great, this would be the flatpak version

```
#!/bin/bash
env -u MOZ_NEW_INSTANCE -u MOZ_NO_REMOTE flatpak run --branch=stable --command=thunderbird org.mozilla.Thunderbird
```

but how to set as a handler?

This is a test: [testlink-to-email](mailto:<email address hidden>)

Okay tried it: created a new desktop entry linking to that script, in KDE set it as Mail program, in Librewolf set mailto to "open with system handler", still the exact same result

Created attachment 9385906
same problem

Thanks from moatausbadun1987.

In Windows, delete the entry in Windows Environment:
In Windows Settings, search for environment | Choose "Edit system environment variables"
Select "Environment Variables" and under "System Variables," DELETE the environment variable MOZ_NO_REMOTE
It doesn't matter whether the variable value is set to 0 or to 1 — the mere presence of the variable appears to cause this problem, including if you try to send an email from Thunderbird from any browser.