![无法在 Ubuntu 14.04 上进行 apt 更新](https://linux22.com/image/1124868/%E6%97%A0%E6%B3%95%E5%9C%A8%20Ubuntu%2014.04%20%E4%B8%8A%E8%BF%9B%E8%A1%8C%20apt%20%E6%9B%B4%E6%96%B0.png)
这是日志。
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used.
GPG error: http://ppa.launchpad.net trusty Release: The following signatures were invalid: BADSIG D530E028F59EAE4D Launchpad PPA for NoobsLab
W: Failed to fetch ppa.launchpad.net/noobslab/apps/ubuntu/dists/trusty/Release
W: Failed to fetch us.archive.ubuntu.com/ubuntu/dists/precise-updates/main/source/Sources Hash Sum mismatch
W: Failed to fetch ppa.launchpad.net/noobslab/apps-dependencies/ubuntu/dists/trusty/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch ppa.launchpad.net/noobslab/apps-dependencies/ubuntu/dists/trusty/main/binary-i386/Packages 404 Not Found
W: Some index files failed to download. They have been ignored, or old ones used instead.