已安装MATE桌面，登录界面无法选择该环境求助

架构老林

2026-5-19

Hey there! I totally get how frustrating it is when you can't access your favorite MATE desktop after installing it—MATE is such a solid, no-nonsense environment, so I'm glad you love it too. Let's work through this issue step by step.

Step 1: Reinstall MATE Core Packages

First, let's make sure all MATE components are properly installed and registered. Run this command in a terminal (you can open one by pressing Ctrl+Alt+T even if you're stuck in Unity):

sudo apt update && sudo apt install --reinstall ubuntu-mate-desktop mate-session-manager

This will refresh your package list, then reinstall the full MATE desktop suite and the session manager—this is the component that tells the login screen about the MATE session option.

Step 2: Verify Session Files Exist

The login screen pulls session options from .desktop files in /usr/share/xsessions/. Let's check if MATE's file is there:

ls /usr/share/xsessions/

Look for files named mate.desktop or ubuntu-mate.desktop. If you don't see either, move to the next step.

Step 3: Manually Create the MATE Session File

If the session file is missing, we'll create it manually. Open a text editor with sudo privileges:

sudo nano /usr/share/xsessions/mate.desktop

Paste the following content into the editor:

[Desktop Entry]
Name=MATE
Comment=This session logs you into MATE
Exec=mate-session
TryExec=mate-session
Icon=mate-logo
Type=Application
Keywords=mate;desktop;

Save and exit: press Ctrl+O, hit Enter to confirm, then Ctrl+X.

Step 4: Restart to Apply Changes

Finally, restart your system or the display manager to let the login screen pick up the new session option. To restart the display manager:

If you're using GDM (default on newer Ubuntu):
```
sudo systemctl restart gdm3
```
If you're using LightDM (older Ubuntu versions):
```
sudo systemctl restart lightdm
```

Or just reboot your system for simplicity: