if you are running windows home server and have run into the "backup stalls out at 79%, then gives error message" situation, please take a look at this post.
i am reposting my comments from the thread View backup stalls out at 79%, then gives error message.
if you have this problem or have had this problem in the past, please post your experiences on the microsoft forum thread.
I was having this problem as well. I am running Windows Home Server RTM on hardware that I built. It has 4 Seagate enterprise edition 500 gb drives in it. It has a new Intel motherboard/cpu. 2 GB of ram. WHS has been running without any issues of any sort as far as I can tell for about two months. I am running the JungleDisk off-site backup plug-in. Other than that the WHS machine is a clean install.
Yesterday, both my Vista laptop and 2003 server were unable to open a backup. I had just opened the backup for the C drive to restore a file (which worked). Then I closed it, realizing that the file that I needed was on the D drive of the backup. So I closed the Explorer window that was Y: or some drive letter like that and clicked on the backup again, selected the D drive from the backup and then the restore dialog would reach 79% and give the "could not connect to the backup service, make sure the service is running" error.
I logged in via Terminal Services to the WHS and check the services. All home server processes were started. I restarted the backup service which didn't help. I rebooted the WHS, didn't help. I rebooted the client machines, didn't help.
Later in the evening a backup of my Vista client succeeded fine but again, I was unable to open it using the restore option.
The most troubling thing about the whole escapade is that today, one day later, I can open the backup and restore files from it with no problem. Thus making this an intermitent and even more serious problem. Backup is one of those areas where "hope" is not a good feeling. I would rather "know" that I am going to be able to restore a file when I need to.
Other than this very serious issue (and the serious issue with data corruption on the shared drives), WHS has a lot of promise. I hope Microsoft takes a proactive stance dealing with these problems and makes this platform rock solid.