场景：
1. 第一次使用Time Machine备份系统时，会出现
time machine the system date and time is incorrect
系统的日期与时间不正确
sudo touch /System/Library/CoreServices/backupd
Solved this myself using some help on another forum in case anyone else ever has this error and finds this post.
Time Machine is powered by a system utility called backupd. For some reason when I installed the OS, the Created & Modified dates for backupd were set in the future relative to the current date. Before TM runs there are some checks to ensure everything is in order, and if backup was created in the future relative to the current date, it fails.
I verified this by running the following Terminal command:
stat /System/Library/CoreServices/backupd
which gave the result:
16777221 11087 -rwxr-xr-x 1 root wheel 0 704064 "Nov 5 15:13:22 2013" "Nov 6 04:54:26 2013" "Nov 6 04:54:26 2013" "Sep 30 07:33:37 2013" 4096 1080 0x20 /System/Library/CoreServices/backupd
You can also just navigate to backupd in the Finder and Get Info and look at the date there if you prefer.
The Nov 5 and Nov 6 dates are the Modified and Created dates. The date at the time I was having the error was Nov 4. Hence why it failed.
We can easily fix this by using the touch command in Terminal. I ran:
sudo touch /System/Library/CoreServices/backupd
[MacOSX]_[Time Machine]_[备份失败的解决办法]
原文：http://blog.csdn.net/infoworld/article/details/44676539