W: GPG error: http://download.opensuse.org Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 85753AA5EEFEFDE9
W: GPG error: http://download.opensuse.org Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 51AFC9B27331E9C4 thx
答案1
将评论转换为答案
您看到的错误是由于您添加了 OpenSuse 存储库。
在 Dash 中搜索软件源并取消选中你在其他软件标签。
关闭并刷新更新管理器
或者 - 从终端运行
sudo apt-get update && sudo apt-get upgrade