不再存在的未知语言的 Latex 错误

Question

我使用运行我的 Latex 文件pdflatex并收到以下错误消息：

! Package babel Error: Unknown language `american'. Either you have
(babel)                misspelled its name, it has not been installed,
(babel)                or you requested it in a previous run. Fix its 
                       name,
(babel)                install it or just rerun the file, respectively.

See the babel package documentation for explanation.
Type  H <return>  for immediate help.
...                                              

l.20 \select@language{american}

我的 .tex 文件以以下内容开头：

\documentclass[a4paper,12pt,ngerman]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{fancyhdr}
\usepackage{a4}
\usepackage[ngerman]{babel} 
...

我删除了 american babel 包并用 ngerman 包替换它。之后我收到了包 babel 错误，尽管 american 包已被删除。

我怎样才能修复这个错误并编译代码？

Answer 1

我删除了创建的 .aux 文件，pdflatex <filename>再次运行后不再出现错误，并且 PDF 已正确构建。