Exchange failed to start the resolution of a failure after two groups were mistakenly deleted in exchange

Recently, I've been trying to learn something about MS and do Exchange 03 experiments. Listening to TechNet's video, after domain expansion, two groups were created, one is Exchange Domain servers, and the other is Exchange Enterprise Servers. These two groups are in the Users container by default. As shown in figure:

The TechNet video says that these two groups cannot remove the Users container, or that Exchange services will not start, and thus not be able to provide services.

In order to do the experiment, the two groups were moved out of the Users container, and sure enough, when the service was restarted, the SA Service and the is service of exchange were not started, and prompted:

Then look at the service and discover that the status of Microsoft Exchange System Attendant is turned on rather than started. The server is not restarted or the service can be serviced properly.

I then moved the two groups back to the Users container, and exchange was able to provide services as usual. In order to further test, I took these two groups to delete, and then the cup, optical system restart on the VM machine spent 3.5 hours, then do not know is the problem or how the virtual machine, can not do domain expansion. The card was not moved there when it was installed. After removing these two groups, another DC in the experimental environment did DomainPrep. I looked up some information on the internet and didn't find much value. So need to change a way of thinking, think of "ad tombstone", see whether from the "ad tombstone" in the marked for deletion of the group to find back, can smoothly provide services. Finally, we found two tools, one is Adrestore.exe, and the other is command line tool. Another is objectrestoreforactivedirectory_10.zip, from a foreign website, seems to say is a not free tool, have the use of the term.

The next step is to restore the deleted group with these two tools, and two methods can be implemented, see figure: