Problem: default user becomes root after `wsl --import` migration/reinstall — whoami changed, permissions broken —— Trove problem library

What you will run into

After wsl --export backup and wsl --import migration/reinstall, whoami inside WSL suddenly shows root: home directory, ssh keys and file ownership are all messed up.

To make it worse, <distro> config --default-user yourusername errors or does nothing — imported distros have no executable launcher, so that command does not apply to them.

Why this happens

The default user of a WSL distro is decided by two sources: the Store distro launcher's default user (what <distro> config --default-user changes), and /etc/wsl.conf [user] default=.

A distro installed via wsl --import has no executable launcher, so config --default-user does not work on it — the official docs say exactly that; the only route is wsl.conf.

The tar produced by wsl --export keeps /etc/wsl.conf inside the distro as-is: if the original distro never wrote [user] default=, nothing specifies a non-root user after import, so WSL starts as root by default.

That explains "it was fine before migration, root after": the problem is not the migration, it is the missing [user] section in the original config.

Deterministic takeaway: after import, whoami = root → first cat /etc/wsl.conf and check for a [user] section — if missing, add it and restart the distro;

config --default-user only works on Store-installed distros, trying it on an imported one is wasted effort.

Step by step

1. Confirm the current state — Must do

whoami          # root = missing [user] config
cat /etc/wsl.conf

2. Write the [user] section — Must do

# The username must already exist (created with useradd or previously used)
echo -e "[user]\ndefault=your-username" >> /etc/wsl.conf

If a [user] section already exists, change only the default= line — don't append a duplicate section header.

3. Restart the distro to apply — Must do

# Run on the Windows side (not inside WSL)
wsl --terminate <distro-name>
wsl -d <distro-name>

wsl.conf is only read when the distro starts; without a restart the change does not take effect.

4. Store-installed distro (not imported) — By scenario

For a normally installed Ubuntu, either <distro> config --default-user <username> (PowerShell/CMD) or the same wsl.conf section works.

How to confirm it works

After re-entering, whoami prints the target username; wsl --user root still switches to root temporarily (--user is a one-shot override and does not change the default); home directory / ssh permissions are back to normal.

Other environments

Symptom

$ whoami
root
$ ubuntu config --default-user myuser   # imported distro: errors or no effect

Signature: normal user before migration/import, root after import; /etc/wsl.conf has no [user] section; config --default-user is ineffective on the imported distro.

Cause

The WSL start user is decided by the launcher's default user or /etc/wsl.conf [user] default=. Distros installed via wsl --import have no executable launcher, so config --default-user does not work; export preserves the original wsl.conf, and when the original config lacks a [user] section the imported distro starts as root.

Solution

1. whoami + cat /etc/wsl.conf to confirm the missing [user] section;
2. echo -e "[user]\ndefault=your-username" >> /etc/wsl.conf (the username must already exist);
3. Restart the distro from Windows with wsl --terminate <distro-name>;
4. Re-enter and verify whoami.

Related canonicals

Read in order: precondition -> same root / same domain / related:

• Related (similar errors, different cause):
• WSL fails to register a distro (same domain: WSL distro lifecycle problems)
• WSL systemd not running (another wsl.conf pitfall: no effect without a distro restart)