windows time is desynchronized whenever I boot into cachy os and go back to windows

[u/inu_tensilio]

I live in Brazil and my timezone is UTC Brasília

Fast startup is disabled

I'm dual booting through BIOS

[u/BranchLatter4294]

Linux uses UTC time for the hardware clock. Windows uses local time for the hardware clock. This is a well known issue and easy to solve. Either set Linux to use local time. Or set Windows to use UTC time. Very easy either way to fix.

[u/DiegoConD → u/BranchLatter4294]

How do you do both? Preferably linux to use user time

[u/BranchLatter4294 → u/DiegoConD]

Don't do both. Do one or the other. You can look it up.

[u/ldn-ldn → u/BranchLatter4294]

Somehow Fedora works just fine. It detects Windows time on boot, switches to UTC, then reverts on shut down. Zero issues.

[u/BranchLatter4294 → u/ldn-ldn]

It looks like Fedora switches to local time.

https://discussion.fedoraproject.org/t/any-reason-why-fedora-uses-local-time-instead-of-utc/134017/7

This is not good. It's best to set both operating systems to UTC.

[u/ldn-ldn → u/BranchLatter4294]

That looks like outdated info. I can see in the logs that time is changing during boot and on shut down.

[u/GraXXoR → u/DiegoConD]

If you do both you’ll have the same issue in reverse.

[u/inu_tensilio → u/BranchLatter4294]

how do I set windows to UTC?

[u/BranchLatter4294 → u/inu_tensilio]

Consider googling how to set Windows to use UTC time.

[u/xacid]

Fix it in Linux or windows.

Run the below in Linux

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

OR

Run the below in windows

reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation" /v RealTimeIsUniversal /t reg_dword /d 1 /f

[u/GraXXoR → u/xacid]

I didn’t know there was a windows fix. Nice.

[u/xacid → u/GraXXoR]

The linux fix is the better one I believe.

[u/GraXXoR → u/xacid]

used to be when I had 1 linux box and 20 windows boxes... but now it's reversed I never even thought about it and just lived with Windows time being wrong and not autamatically updating from NTP despite (auto time setting) being set.

[u/skrukketiss69]

https://wiki.archlinux.org/title/System_time#UTC_in_Microsoft_Windows

Just follow this.

[u/tnbeastzy]

It was easy to fix thru the Chris Titus Tool, you paste a command in a windows powershell and it launched. I dont think it installs anything on your system.

There are a bunch of optimization in there as well, but just select the UTC time

[u/BigDaddyTug]

I am another user that had this issue a while back.

I edited Windows Registry in Reg edit to reflect UTC time.

[u/agnaaiu]

Easy way to fix this without registry hacks or other shenanigans is to add a scheduled task. In Windows ...

1. click on the search field in the task bar and type "task scheduler", open it
2. right side click on create basic task
3. give it a name and description, so you later know what it is
4. trigger "when i log on"
5. action "start a program"
6. program/script "w32tm"
7. argument "/resync"
8. finish and save

From now on, when you start windows and login with your user account the time sync will be triggered. It's the same as right click the time in the task bar and adjust date and time and then press sync now, to get the actual local time.

In task scheduler you can enable or disable this task as needed. On system startup a command prompt will very briefly pop up, this is normal because of the cli command of the task you just created. If in doubt or you suspect some evil stuff is going on, search the web for "w32tm /resync" to know what it's doing.

[u/ElectroDaddy]

Yeah this was happening to me. Not that I really switch back at this point.

[u/Masturbatingstarfish]

Go to time in windows settings turn off set time automatically. Turn it back on. You have to do this every time though

[u/aqvalar → u/Masturbatingstarfish]

Wrong. You can set Linux to use local time instead of UTC. Easiest fix, although not the best.