如题，今天在终端使用sudo apt-get dist-upgrade命令之后重启发现无法进入gnome和默认Ubuntu图形界面了！但是命令界面还是可以正常进入的，gnome和默认图形界面总是输入密码闪一会然后又回到密码输入界面，无限循环，但是试了一下可以进入xfce的界面，Ubuntu默认和gnome都进入不了，有谁知道是什么原因吗？

设法执行以下指令
sudo apt install pastebinit

设法执行以下指令将结果全部复制贴上来

结果就是这样的

xinglingwu@xinglingwu-Lenovo-M490:~/桌面$ sudo cat /var/log/apt/history.log | pastebinit
[sudo] xinglingwu 的密码：
Failed to contact the server: [Errno socket error] The write operation timed out
xinglingwu@xinglingwu-Lenovo-M490:~/桌面$ lspci -knn | grep -iA2 'vga\|3d\|disp'00:02.0 VGA compatible controller [0300]: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09)
Subsystem: Lenovo 3rd Gen Core processor Graphics Controller [17aa:5003]
Kernel driver in use: i915
--
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GF108M [GeForce GT 635M] [10de:0de3] (rev a1)
Subsystem: Lenovo GF108M [GeForce GT 635M] [17aa:5003]
Kernel driver in use: nvidia
xinglingwu@xinglingwu-Lenovo-M490:~/桌面$ sudo lshw -C display
*-display
description: VGA compatible controller
product: GF108M [GeForce GT 635M]
vendor: NVIDIA Corporation
physical id: 0
bus info: pci@0000:01:00.0
version: a1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
configuration: driver=nvidia latency=0
resources: irq:16 memory:f2000000-f2ffffff memory:e0000000-efffffff memory:f0000000-f1ffffff ioport:3000(size=128) memory:f3000000-f307ffff
*-display
description: VGA compatible controller
product: 3rd Gen Core processor Graphics Controller
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
version: 09
width: 64 bits
clock: 33MHz
capabilities: msi pm vga_controller bus_master cap_list rom
configuration: driver=i915 latency=0
resources: irq:28 memory:f3400000-f37fffff memory:d0000000-dfffffff ioport:4000(size=64)
xinglingwu@xinglingwu-Lenovo-M490:~/桌面$

问题解决了，不知道是基于什么样的原理，我将N卡的驱动卸载了重装之后接进去了，希望知道原理的大神说下是什么原因，好让后来看的人知道

和楼主有相同问题，卸载nvidia官方驱动后可以进入默认桌面环境。不卸载的话可以进类似fluxbox这样的轻量级桌面环境。