Failed to set timezone: Invalid argument – timedatectl in Kali Linux

The direct answer

timedatectl rejects a timezone with Failed to set timezone: Invalid argument because the identifier you supplied does not exist in the IANA timezone database. The check happens inside the systemd-timedated D-Bus service before anything touches /etc/localtime, so the error is a validation failure, not a permission or filesystem problem. Separately, on a Kali live boot, even a successful timezone change vanishes at reboot because the live overlay treats /etc/localtime as volatile — that is expected behavior, not a bug.

Why the error says "Invalid argument"

When you run timedatectl set-timezone Some/Zone, systemd-timedated looks up the identifier under /usr/share/zoneinfo. If no matching file exists, the service returns an invalid-argument error over D-Bus and timedatectl prints the message and exits non-zero. Nothing is modified. Common triggers:

• Typos or wrong casing — identifiers are case-sensitive (america/new_york fails; America/New_York works).
• Invented zones like US/Eastern Standard Time or EST5EDT-style guesses that aren't in the database.
• A minimal or corrupted tzdata installation where the zoneinfo tree is incomplete.

Verify the identifier before setting it:

timedatectl list-timezones | grep -i york
sudo timedatectl set-timezone America/New_York
timedatectl show

If a zone you expect is missing from the list, reinstall tzdata (sudo apt install --reinstall tzdata) rather than forcing the symlink by hand.

Why changes don't survive a live reboot

In a standard Kali live session the root filesystem is a read-only base plus a RAM-backed overlay. /etc/localtime is a symlink into /usr/share/zoneinfo, and the updated symlink lives only in the volatile overlay. Reboot, and you're back to the default (typically UTC). This applies to every live change, not just timezones.

Making the timezone persistent

There is no documented Kali option that persists /etc/localtime without configuring persistence — that is the designed mechanism. The workflow:

1. Create a persistence partition labeled persistence on the USB drive (the Kali docs walk through this with fdisk/mkfs.ext4).
2. Mount it and write a persistence.conf. The broad option is / union, which persists the whole filesystem including /etc/localtime. If you want a narrower scope, add a bind entry covering /etc instead — but be careful: malformed persistence.conf syntax can silently disable persistence entirely, losing all changes.
3. Boot with the persistence option selected from the live boot menu.
4. Set the zone once: sudo timedatectl set-timezone Europe/London.
5. Reboot and confirm: timedatectl show should report the same Timezone= value, and ls -l /etc/localtime should point at the right zoneinfo file.

If you can't or won't use persistence

For one-off live sessions, a boot parameter or a startup script that runs timedatectl set-timezone (or sets the TZ environment variable for the tools that need it) is a pragmatic alternative. Note that TZ only affects processes that read it — system services and logs still follow /etc/localtime.

Uncertainty notes

Exact persistence.conf entry syntax and boot-menu wording vary slightly across Kali releases; check the current Kali persistence documentation for your version before rebuilding the partition. The validation behavior and the volatile-overlay explanation above are stable across systemd-based Kali releases.