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Windows 11 preview update results in invalid certificate error - timezone change

Thunderbird Zaklučowanje
evilspoons je před před 1 hodźinu wotmołwił
evilspoons
evilspoons

Hi there.

I'm in Alberta, where we have recently changed timezones. Note that the CLOCK has not changed yet, as we are still before the date in November when we would "fall back". We were UTC-6 summer and UTC-7 winter. Windows called this "Mountain Time (USA and Canada), but now the "Mountain Time (Alberta)" timezone is in Windows after the 2026-09 Preview Update (KB5124010) (26300.9550).

When connecting to Shaw.ca's IMAP servers, the certificates that were valid prior to the Windows update are now reported as invalid. This has been confirmed across two separate PCs with different email accounts. The data for the certificate LOOKS valid (see screenshot) and is the same before and after the timezone change.

The failure occurred on the latest ESR release of Thunderbird, as well as 156.0 and 157.0 non-ESR.

Thanks :)

Hi there. I'm in Alberta, where we have recently changed timezones. Note that the CLOCK has not changed yet, as we are still before the date in November when we would "fall back". We were UTC-6 summer and UTC-7 winter. Windows called this "Mountain Time (USA and Canada), but now the "Mountain Time (Alberta)" timezone is in Windows after the 2026-09 Preview Update (KB5124010) (26300.9550). When connecting to Shaw.ca's IMAP servers, the certificates that were valid prior to the Windows update are now reported as invalid. This has been confirmed across two separate PCs with different email accounts. The data for the certificate LOOKS valid (see screenshot) and is the same before and after the timezone change. The failure occurred on the latest ESR release of Thunderbird, as well as 156.0 and 157.0 non-ESR. Thanks :)
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evilspoons
evilspoons Prašer

Update: I manually set my timezone back to the old one (the one that will switch back to UTC-7 in November) and I can check my email again, so it seems like it's explicitly tied to the new timezone rather than something else in the Windows update.

Stajće prašenje

Dyrbiće so pola swojeho konta přizjewić, zo byšće na přinoški wotmołwił. Prošu stajće nowe prašenje, jeli hišće wužiwarske konto nimaće.