Switch User button on lock screen allows shutdown without warning, leading to data loss

Distribution

Mint 22.1 x86_64

Package version

6.4.8

Graphics hardware in use

Dell laptop, Intel integrated graphics

Frequency

Always

Bug description

On the lock screen, the Switch User button sends the user back to the login screen.
From there, the Shutdown and Reboot buttons are available and can be triggered without any warning about active sessions.

This causes:

Data loss risk: if shutdown/reboot is clicked (intentionally or by accident), the active user session is terminated immediately, even with unsaved work.

Multi-user risk: if a second account is started and then shuts down the system, the first user’s session is killed immediately without notifying them. Any unsaved documents are lost unless the application autosaves them.

Another user confirmed this behavior:

“If you have open documents in one account, switch to another account with the original account still running, and then perform a shutdown from the second account, the shutdown happens immediately without prompting you about the other account having open documents and programs. Any unsaved documents are lost unless the program autosaves them. This is definitely a bad thing, and I would consider it a bug that could lead to lost data.”

Steps to reproduce

1. Log in with User A and open some documents/programs.

2. Lock the screen.

3. Click the Switch User button.

4. At the login screen, either:

Click Shutdown / Reboot, OR

Log in as User B and perform a shutdown.

5. Observe that User A’s session is terminated without any warning.

Expected behavior

The system should warn about active sessions or unsaved work before allowing shutdown/reboot.

Alternatively, shutdown/reboot from the login screen should require authentication if another session is active.

Additional information

Tested on Cinnamon 6.4.8, Mint 22.1 .

Issue is reproducible every time.

This is not a cosmetic issue — it can lead to serious data loss if unsaved documents are open.

Start by reproducing the lock-screen to Switch User flow on Cinnamon 6.4.8, including shutdown from the login screen and from a second account. Trace the login-screen shutdown and active-session handling entry points. Done means shutdown or reboot warns about active sessions or requires authentication, with the documented reproduction steps no longer allowing silent termination.