After testing that the virtual machine can access the Internet, you need to set up the "ubuntu code download source", and then turn off "automatically check for updates". The purpose is to prevent Ubuntu from being upgraded to a higher version, which will make us unable to use it .
1. Click the "Show Applications" icon
Get the following interface:
2. Enter " Software and updates" in the "Enter to search box" in the picture above, as shown in the picture below:
3. Double-click "Software and Updates" and wait for 1 minute. The following interface will pop up:
If you use a Chinese server, the download speed will be faster .
4. Click "Update" to get the following picture:
5. Set "Automatically check for updates" to "Never" to prevent Ubuntu from being upgraded to a higher version, making it unusable . See below:
6. Click "Close" to get the following picture:
7. Click "Edit" and see the following operation:
8. Click "Preferences (R)..." to get the following picture:
9. Click "Update" to get the following picture:
10. Uncheck "Check for product updates at startup" and uncheck "Automatically update in virtual machine", as shown below:
11. Click "OK".