an unexpected error has occurred. the required components were not found

The Software Update server for El Capitan does not have the extra pieces. It won't work until Apple posts them.

I had the same issue, and found a solution that at least worked for me!

For some reason, manually installing the "Remote Desktop Client Shell 3.8.0" update from my servers software update data folder seemed to do the trick!

To get the update, (Assuming you have Server 5 installed), enable and download the update listed above. It is number 031-23124, and once you download it it will be in the folder.

/Library/Server/Software Update/Data/html/content/downloads/59/10/031-23124/x0sj4t1vbimv6h3ejhjzf3nwa6vt 9ekxgd/

Install that, and you should be all good!

Hi,

I have got a feeling this is a truly dumb question but I need to ask... I have Remote Desktop installed on my desktop computer, not a server. I also have Server 5 installed on this computer although I don't use it. I have found the update you list; however, where do I install it?

Thanks.

OK, so your desktop computer is actually a server, all macs running 10.7 or later are. All the server app does is let you manage the services that OS X has built in. Assuming you are having the same error as the one in the origonal post, all you do to install the update is run the pkg file that i mentioned in my first post. The folder path in my first post has a space that shouldnt be in it for some reason, so keep that in mind.

That worked. I found the folder you specified but didn't look at it carefully enough and didn't see the installer package. Once I dragged it over from our server to my desktop and installed it, it worked like a dream. Thank you for the help - much appreciated.