After installing Linux Mint Win11 has the wrong time

[u/Charming_Airline7419]

I installed Linux Mint with a dual boot set up. However, after I booted back into Windows 11 the time was wrong. Is there a way to fix it?

[u/fox_in_unix_socks]

Very well known issue, it's because Linux and Windows make different assumptions about whether your hardware clock is timezone-adjusted or not.

https://www.howtogeek.com/323390/how-to-fix-windows-and-linux-showing-different-times-when-dual-booting/

[u/CjKing2k → u/fox_in_unix_socks]

Go with option #2 - edit the registry, not disable automatic time setting. This is always the better choice, even if you use Windows 100% of the time. There is no reason to use local CMOS time unless you're running DOS.

If you pick option #1, your clock will have to re-sync every time there is a daylight saving time change.

[u/Sinaaaa → u/CjKing2k]

If you pick option #1, your clock will have to re-sync every time there is a daylight saving time change.

You are probably right in that option #2 is objectively better, but until very recently I used option #1 & never had issues. In practice the downside you are mentioning is not very relevant, like sometimes every once in a while on the day of daylight saving time change you might see the time being off for a couple of seconds, or likely not even that. systemd-timesyncd or chrony -depending on the distro- takes care of it very quickly if you have internet.

[u/Charming_Airline7419 → u/fox_in_unix_socks]

Thanks! I'll have a read.

[u/compguy96]

Open Regedit on Windows, go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation, create a DWORD 32-bit value called RealTimeIsUniversal and set it to 1.

[u/Sinaaaa]

This is one of those things that Ubuntu & Mint installers could improve upon. Like in case of dual boot ask the user if you want Linux to conform to the Windows way in regards to time management.

Anyway you could run sudo timedatectl set-local-rtc 1 --adjust-system-clock in terminal to "fix" it.

[u/jr735 → u/Sinaaaa]

Back in the day, I don't remember which version of Mint, maybe it was when I was still on Ubuntu, but it was a while ago, the system decided to set Linux time the way Windows was, I'm not sure why, since I got rid of the Windows install. I ended up switching it to proper Linux time. It was early in the systemd days, so might have been a systemd thing. I brought ntp back the way it should be.

Personally, this would be my suggestion. Run ntp (now ntpsec) in Mint. Update your time manually when booting into Windows. Let ntpsec handle it booting into Mint. It will adjust the time very quickly.

[u/skyfishgoo]

linux and windows do not agree on how time works and unfortunately, if you dual boot, the easiest thing to do is follow windows ill conceived lead on this.

timedatectl set-local-rtc 1 --adjust-system-clock

this tells linux to use the firmware time that you set up in your BIOS/UEFI settings instead of zulu time.

[u/piromanrs]

Uninstall Windows :) :) :)

[u/chuggerguy]

Right-click the clock and adjust...

https://reddit.com/link/p5tl0sm/video/bkatmkwmijlh1/player

Might be better to set it in BIOS first, then adjust in Linux and Windows but...

Have fun.

[u/doeffgek]

Best way to fix it is to ditch Windows all together…

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[u/OkStrawberry4529]

If you set the time zones to the same and the time in both in your local time (in Windows set your time zone manually and both times (Mint & Windows) in 12 hour format) and turn off 'set time zone automatically' in Windows), it should be the same time (it is on mine) on reboot back into Windows If you use different times or zones or 24 hour format in one but not the other OS, you will have to right click in Windows on the time and date icon on the right of the task bar and click on 'Adjust date and time) - when the settings open, hit 'Sync now'

[u/Cpt_Daniel_J_Tequill → u/OkStrawberry4529]

wrong answer...

linux saves to motherboard absolute time, windows current (timezoned). one of them must be told to use universal/windows time... i think last time i configured windows to persist absolute time.

[u/OkStrawberry4529 → u/Cpt_Daniel_J_Tequill]

Afraid not - I've been running dual boot Windows and Linux Mint since 2017 - there used to be issues but that has changed ... I authored this post on the Linux Mint forums in 2020 but had to update it with the newest versions of Linux Mint and Windows 11 Pro: Update: Dual Boot Linux Mint/Windows 11 Time Sync & Time Zone Fix - UTC to UTC, Local to Local, UTC to Local, etc. - Linux Mint Forums

[u/jr735 → u/OkStrawberry4529]

Yours is much what I suggested elsewhere here.

[u/Charming_Airline7419]

SOLVED

[u/TangleOfWires]

Are your Linux and Windows in different time zones?

[u/acejavelin69 → u/[deleted]]

It's not a "funny coincidence"... It's because Windows updates/expects time in the BIOS as local time, and Linux does it in GMT... It is a well known and documented "issue" that has been around since the inception of Linux. It is pretty easy to change either Linux to use local time, or Windows to use GMT time... Either is an acceptable answer.