macOS 10.14 mojave安装低版本iTunes 12.6.x

下载iTunes 12.6版本：https://support.apple.com/zh-cn/HT208079

安装低版本iTunes

利用脚本编辑器运行脚本安装低版本iTunes：

关闭SIP系统完整性保护

• 打开Mac终端输入命令：csrutil status

$ csrutil status

• 默认情况下是开启的

System Integrity Protection status: enabled.

• 重启电脑，按住键盘上面的cmmand+r，进入修复模式
  点击实用工具，选择终端
  

输入命令：csrutil disable

$ csrutil disable

• 再次重启电脑

• 建议这里记得安装完成后改回来，开启SIP和前面的操作一致，在修复模式下，输入命令csrutil enabled

$ csrutil enabled

打开脚本编辑器，将以下代码复制到脚本编辑器运行（卸载iTunes并重装）

set question to display dialog "Delete iTtunes?" buttons {"Yes", "No"} default button 1
set answer to button returned of question
if answer is equal to "Yes" then
    do shell script "rm -rf /Applications/iTunes.app" with administrator privileges
    display dialog "iTunes was deleted" buttons {"Ok"}
    set theDMG to choose file with prompt "Please select iTunes 12.6 dmg file:" of type {"dmg"}
    do shell script "hdiutil mount " & quoted form of POSIX path of theDMG
    do shell script "pkgutil --expand /Volumes/iTunes/Install\\ iTunes.pkg ~/tmp"
    do shell script "sed -i '' 's/18A1/14F2511/g' ~/tmp/Distribution"
    do shell script "sed -i '' 's/gt/lt/g' ~/tmp/Distribution"
    do shell script "pkgutil --flatten ~/tmp ~/Desktop/iTunes.pkg"
    do shell script "hdiutil unmount /Volumes/iTunes/"
    do shell script "rm -rf ~/tmp"
end if
if answer is equal to "No" then
    display dialog "iTunes was not deleted" buttons {"Ok"}
    return
end if

set question to display dialog "Install iTtunes?" buttons {"Yes", "No"} default button 1
set answer to button returned of question
if answer is equal to "Yes" then
    do shell script "open ~/Desktop/iTunes.pkg"
    return
end if
if answer is equal to "No" then
    display dialog "Modified iTunes.pkg saved on desktop" buttons {"Ok"}
    return
end if

运行后根据提示卸载安装。

如果提示 iTunes Library.itl 错误，打开终端运行命令：sudo rm ~/Music/iTunes/iTunes\ Library.itl

$ sudo rm ~/Music/iTunes/iTunes\ Library.itl

或者：

display dialog "Please select iTunes 12.6 dmg file" buttons {"Ok"}
set theDMG to choose file with prompt "Please select iTunes 12.6 dmg file:" of type {"dmg"}
do shell script "hdiutil mount " & quoted form of POSIX path of theDMG
do shell script "pkgutil --expand /Volumes/iTunes/Install\\ iTunes.pkg ~/tmp"
do shell script "sed -i '' 's/18A1/14F2511/g' ~/tmp/Distribution"
do shell script "sed -i '' 's/gt/lt/g' ~/tmp/Distribution"
do shell script "pkgutil --flatten ~/tmp ~/Desktop/iTunes.pkg"
do shell script "hdiutil unmount /Volumes/iTunes/"
do shell script "rm -rf ~/tmp"

set question to display dialog "Install iTtunes?" buttons {"Yes", "No"} default button 1
set answer to button returned of question
if answer is equal to "Yes" then
    do shell script "open ~/Desktop/iTunes.pkg"
    return
end if
if answer is equal to "No" then
    display dialog "Modified iTunes.pkg saved on desktop" buttons {"Ok"}
    return
end if

运行脚本卸载iTunes后，按照脚本提示选择12.6版本iTunes的安装包进行安装即可。