User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:98.0) Gecko/20100101 Firefox/98.0

Steps to reproduce:

Changed "week starts on" day to Sunday in Calendar
Check Calendar view, updated view starts on Monday
Close app, shut down computer
Overnight
Next day, restart, launch TB

Actual results:

Calendar week starts on Monday
It just seems to lose the user setting, and uses its default value instead

Expected results:

Calendar should have remembered Sunday as a week start day

Thank you.

In the last year we fixed this area twice? bug 1689775, bug 1734504
Another regression?
More tests needed?

I am going by usage.
I have to reset it to "Sunday" perhaps once a month or so. Sometimes in quick succession between restarts.

Not sure if this value is saved when TB is updated between versions?
One thought was maybe "Monday" is introduced when TB gets self-updated.

I'm using 91.11.0 (64-bit) on Linux, and this problem still persists. At each reboot the start of week resets to Monday.
(No updates to TB involved)

(In reply to tsvibar from comment #3)

I'm using 91.11.0 (64-bit) on Linux, and this problem still persists. At each reboot the start of week resets to Monday.
(No updates to TB involved)

I know a similar-ish issue like this was happening even post 91.0 and, I think, didn't get resolved until closer to the 102.x release. Likely related to bug 1734504 and, probably, a bit of bug 1648718 as well.

Although I would wait until 102.1.0, is 102.0.3 available to you for your Linux distro? If so, you could back up your 91.x profile and try updating to 102.0.3 if you're comfortable? I would wait until 102.1 is released (should be Tuesday) for your distro though as a lot of issues post 102.0.0 > 102.0.3 were fixed and might not affect you as much when you update. Just my 2 cents.

Thanks.
I use Debian bullseye, so I doubt there will be a distro package for the newest version of TB. I'll wait and see.
(The unstable sid is up to 102.0.2)

(In reply to tsvibar from comment #5)

Thanks.
I use Debian bullseye, so I doubt there will be a distro package for the newest version of TB. I'll wait and see.
(The unstable sid is up to 102.0.2)

Ah, ok. It might be a while then before 102.1 sees the light of day for you. You'll likely see 91.12.0 before 102.1.0.

I'm using thunderbird 102.2.1, and the bug is still there:
Several times a week, I have to set "Start the week on" to "Sunday",
and after one or more restarts of thunderbird,
it is automagically reset to "Monday".

So the bug is not fixed in 102.1.x or later.
Even worse, it looks like the bug happens more often in 102.x than before.
Very annoying.

This is on gentoo, i.e. a with a thunderbird 102.2.1 compiled locally from the sources.

I'm not sure, but for me, the problem seems to happen mainly on weekends.
Could the bug be somehow related to the current day of week being saturday or sunday?

This problem occurred for me yesterday (Monday) after updating to 102.5.1
This problem seems to only occur when start of week is set to Sunday.
All other days of the weeks stick.

Also, I have discovered:
Changed start of week to Sunday.
Closed Thunderbird
Opened Thunderbird
Start of week remained at Sunday
Closed Thunderbird
Opened Thunderbird
Start of week now Monday.
I tried this four times and it consistently happened.

@keldyonline, the reporter from bug 1800403 also added:

I created a new blank profile
I found the useragent thingy (in case that is useful to you) Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0
My regional preference is ["en-AU"] and my system locales are ["en-GB","en-AU"]

Given that this is reproducible on a blank profile with those settings, it should be possible to reproduce and fix this.

(we like to have Version reflect the oldest report of the bug, not the most recent)

Today (Wednesday), for the very first time I have ever seen, start of week was still Sunday.
It remained at Sunday after closing and opening Thunderbird once but changed back to Monday again.

Bug still there in 102.6.1.

Can we pleeeeeaaaase have this very annoying bug fixed?!

Check the pref calendar.week.start - it should be 0 for sunday, 1 for monday.

For people seeing this, please go to the Error Console (Ctrl+Shift+J) and enter Services.intl.getCalendarInfo(); then report the settings it shows

The only code I see writing to the pref is https://searchfox.org/comm-central/rev/48761440bd1789596d664f5520429a45c3909d18/calendar/base/content/calendar-chrome-startup.js#254 and that happens when it's a mismatch with system settings.

1. Calendar view was Mon - Sun,
2. Tried Services.intl.getCalendarInfo(); and it showed 1
3. Changed the settings to a Sun - Sat view,
4. Tried Services.intl.getCalendarInfo(); again, still showed 1

Make of that what you will...

Same here: calendar.week.start is correct,
but Services.intl.getCalendarInfo(); shows "firstDayOfWeek: 1" in both cases.

Maybe look at the code the other way - ask how is the start day being saved from adjustment in the UI code? Because the UI does change (admittedly on refresh, it's not on save of settings being adjusted (Win10 experience)). Perhaps this UI setting change is not being reflected back to the right persisted setting at all. Sufficient then for the UI to remain constant under certain conditions, but not good enough to survive an update to the program, which seems to be when it resets itself to Sun start.

(In reply to David Day from comment #20)

Maybe look at the code the other way - ask how is the start day being saved from adjustment in the UI code? Because the UI does change (admittedly on refresh, it's not on save of settings being adjusted (Win10 experience)). Perhaps this UI setting change is not being reflected back to the right persisted setting at all. Sufficient then for the UI to remain constant under certain conditions, but not good enough to survive an update to the program, which seems to be when it resets itself to a Monday start.

The bug is still present in TB 102.10.1, and still annoying.

It is not related to version updates: The start of the week is often reset to monday without updating TB, and on the other hand, it sometimes survives TB version updates without being reset to monday (at least, without being reset to monday immediately or on the next restart).

Another wild guess (I had a similar problem with preference settings in some Xfce panel plugins):
Could the problem be related to some configuration writeback on TB termination, and to being killed too early?
That was a problem in Xfce: On logout or shutdown, the plugins were told to terminate themselves, and they started saving their preference settings to disk. Most of the time, that worked fine, but sometimes, the writeback took too long, and the plugins were killed before they completed saving their state. Next time, they started with some preferences reset to default, because their modified settings didn't make it to the disk...

I haven't been able to reproduce this bug, but I believe I've found the cause and have a solution. Given that I can't reproduce it, however, I'm not certain that the fix works. As such, if someone experiencing this could download and try out a build from https://treeherder.mozilla.org/jobs?repo=try-comm-central&revision=2ddaf75d86708270f7085ffb6e329cafd11f7b6b, I'd appreciate it.

Please note that I expect that values will be reset the first time this build is run, but your settings should hopefully persist on subsequent restarts.

102.11.2 here. (W7 32)
Week start reset to Monday on update from previous version. Configured to Sunday (again), closed Thunderbird, started again, it stayed on Sunday.
So apparently it is reset on upgrades.
I'll let you guys know on next update.

I've done some more thinking on this issue, and I don't believe that the approach I took in the above patch is the right one. I think we should not be relying on preferences for providing the "default" value, and I think that setting those preferences now will make it harder to do the right thing in the future: if the user explicitly sets a preference, we should use that, but otherwise we should ignore preferences and directly use the locale setting.

102.12.0 reset to Sunday on update in W7 (32-bit), though it updated OK in Linux. Can this be related to some locale settings ? My W7 is Spanish version while my Linux is a mix of local time formats and English language. Both have "the same profile", copied over from an older W7 Spanish.

I meant it reset to Monday...

The bug is still present in 102.13.0.
Could we please have this silly annoyance fixed?!

(In reply to Klaus Kusche from comment #29)

The bug is still present in 102.13.0.

As noted above, we are aware of the bug but have not fixed it yet. The fix is not trivial, and it will not be backported to 102.

I think that this bug is related to the visibility of the column in the titles messages list window part. It is a question of preferences. All change on the column will be lost on upgrade. I have not found a report on this.

Can anybody here confirm whether this is still happening or not in Thunderbird 138?

(In reply to Geoff Lankow (:darktrojan) from comment #34)

Can anybody here confirm whether this is still happening or not in Thunderbird 138?

Happened to my in the last 2 weeks. Can remember the version of Thunderbird. Holding thumbs its fixed now.

(In reply to Geoff Lankow (:darktrojan) from comment #34)

Can anybody here confirm whether this is still happening or not in Thunderbird 138?

I cannot confirm for Thunderbird 138 but I can confirm it still happening for 128.10.1esr but not on restart, only after an updating to a minor release. It is the same for some other parameters as shown columns (is it relied ?).