说来也是奇怪，今天在一台 FreeBSD 服务器上安装 git 时，出现了一个错误：
# pkg install git
...
Checking integrity... done (0 conflicting)
[1/48] Installing tpm-emulator-0.7.4_2...
===> Creating groups.
Using existing group '_tss'.
===> Creating users
Creating user '_tss' with uid '601'.
pw: user '_tss' disappeared during update
pkg: PRE-INSTALL script failed
最后解决的办法却是出奇的简单，输入命令 vipw，然后直接 :wq 保存退出，最后再重新安装 git 就可以了。
# vipw
# pkg install git