Hi,

Try to install OS only with mouse (it can be done so) and when you will need to enter username during the installation, use keys on the right side of the keyboard. In my case the numeric keypad was on under those keys and I had to use only numbers, but it worked. After the installation go to Settings/Keyboard.../General and turn off Numeric Keypad (using mouse) and the ordinary keyboard should work. Hope this will get you some help.

Done it on macbook4.1 2008.

It sounds like you're having trouble with keyboard recognition during the installation of Deepin on your iMac. Here are a few steps you can try to resolve the issue: receiptify

1. Check USB Ports: Make sure you're using a USB port that is functioning properly. Try different ports on your iMac.
2. Try Different Keyboards: If you have access to another USB keyboard, try using that one. Some keyboards may have compatibility issues.
3. Boot into Live Environment: If you're using a Live USB, boot into the Live environment first and check if the keyboard works there. If it does, you might have more success during installation.
4. BIOS/EFI Settings: Check your iMac's BIOS/EFI settings (if accessible) to ensure that USB legacy support is enabled. This can sometimes help with keyboard recognition.
5. Update USB Drivers: If you're able to boot into another operating system (like macOS), make sure your USB drivers are up to date.
6. Recreate the Installation Media: There might be an issue with the installation media itself. Recreate the USB installation drive using a tool like Rufus or Balena Etcher.
7. Use a Wired Connection: If you're using a wireless keyboard, try switching to a wired USB keyboard, as it might have better compatibility during installation.