错误提示：

There are unfinished transactions remaining. You might consider running yum-complete-transaction, or "yum-complete-transaction --cleanup-only" and "yum history redo last", first to finish them. If those don't work you'll have to try removing/installing packages by hand (maybe package-cleanup can help).

这种情况是由于在使用yum命令安装程序时，强制退出yum或者yum异常退出造成的，再次使用yum时就会提示上述的错误。

解决方法：

1、安装yum-complete-transaction，这个工具是在yum-utils这个包里面，所以，需要先安装yum-utils才能使用yum-complete-transaction

[root@localhost ~]# yum -y install yum-utils

2、清理缓存

[root@localhost ~]# yum clean all

3、执行清理未完成事物

[root@localhost ~]# yum-complete-transaction --cleanup-only

注意：运行上述命令需要root权限。yum会把下载的软件包和header存储在cache中，而不会自动删除。可用yum clean headers清除header，yum clean packages清除下载的rpm包，yum clean all全部清除。