sddm-greeter problems - black screen on log in

[PaulG]

I have just finished installing Debian 10.5 with LXQT.
I am having problems logging in because when the system boots I am taken to the log in screen, but it remains totally black, with the mouse pointer visible and moveable. If I scan carefully with the mouse, I am able to find the input fields for user name and password, and I can click there and log in. Alternatively, I have been able to log in via Ctrl+Alt+F1, then use startx to get to a working desktop.
From a terminal, I have run sddm-greeter --test-mode, and this confirms the same behaviour. Here is the result when sddm-greeter --test-mode is run-

Code: Select all

$ sddm-greeter --test-mode
[12:36:27.035] (II) GREETER: High-DPI autoscaling not Enabled
[12:36:27.684] (II) GREETER: Reading from "/usr/share/xsessions/lxqt.desktop"
[12:36:27.692] (II) GREETER: Loading theme configuration from "qrc:/theme/theme.conf"
[12:36:27.736] (EE) GREETER: Socket error:  "QLocalSocket::connectToServer: Invalid name"
[12:36:27.803] (II) GREETER: Loading qrc:/theme/Main.qml...
[12:36:28.374] (II) GREETER: Adding view for "VGA1" QRect(0,0 1280x1024)
[12:36:28.539] (WW) GREETER: QOpenGLShader: could not create shader
[12:36:28.543] (WW) GREETER: QOpenGLShader: could not create shader
[12:36:28.619] (WW) GREETER: QOpenGLShader: could not create shader

I would appr4eciate if anyone can give me some guidance on how to fix this. Please let me know if I can provide any other information that is helpful.
System information -
Dell Dimension 3000
CPU: Single Core Intel Pentium 4 (-MCP-) speed: 2793 MHz
Kernel: 4.19.0-10-686-pae i686
Mem: 409.3/993.4 MiB (41.2%)
Storage: 37.25 GiB (11.6% used)

[eriefisher]

Try changing the theme. Better yet switch to LightDM. That's what I did.