@Jbob @george142 I will continue to test this, but so far - yes, @george1421 you are correct in your assessment.
@Jbob Not coarse at all - it’s a reality. Incidentally, re-installing the FOG client after the W10 version upgrade DOES NOT resolve the issue. So far the only thing that works is starting from scratch and letting W10 do it’s thing and THEN installing the FOG client.
I hope I am doing something really dumb and I am the only person experiencing this. 
@george1421 It appears the issue is only with v1511. And currently it appears that it only breaks if I upgrade the PC with the FOG client installed. Preliminary tests indicate that I can load Windows from scratch, do ALL updates, then load the FOG client - and it works!! However, if the FOG client was installed prior to the v1511 update, and then the PC goes through that upgrade process - it breaks the client.
@Tom-Elliott THIS IS NOT SOLVED! I am using the production version of 1.2 with the client that came with server 1.2. The client works great on ALL PC’s in my environment until you run a W10 version upgrade through Windows update, then it breaks the client.
I did try to upgrade to the NEW client, which obviously did not work.
I am now trying to load Windows 10 from scratch, do all the updates - and THEN install the FOG client.
@george1421 George, just saw this post from Tom Elliot:
om Elliott Senior Developer
5 months ago @el-psycho
@el-psycho the new client can only be used with the development versions of fog. This is because the new client was coded along side the development versions. And believe me there are a lot of changes to make it work. The compatibility of legacy and new clients is still present, but 1.2.0 will NOT work with the new client.
So downloading the new client is not a viable option based on this info.
@george1421 I have tried using the new client and it fails on install wanting some CA Certificate?? Then I thought I read that you can only use that client on the server that matches that client. If someone knows otherwise, let me know. Right now I am trying a fresh install of W10 and all updates PRIOR to client install to see if it works.
@Tom-Elliott I am using FOG 1.2 and the values I am using in the AD settings are:
Join Domain after task: “Check”
Domain name: VBS
OU: blank
Domain username: “username only” no domain
Password: “ecrypted with fogcrypt”
Frankly, though, this information is irrelevant because as you can read from my first post - it is working on ALL clients (all 1100) PRIOR to the Windows 10 update. Any device that gets the update (I am speculating, but W10 just pushed out a version update) those devices now fail. So, I can literally image a machine with an image that was created prior to that update and it works fine, renames and joins the domain. If I image a client with an image that includes that Windows update, it no longer will rename or join the domain.
I appreciate the help!
…sorry, premature submission.
Can someone help me out here? FOG is the lifeblood to our school district and it just came to a grinding halt. It won’t add printers, change client name or ad to AD. Here is the error:
HostnameChanger Domain Error! (‘Unknown Error’ Code: 2725)
After a recent batch of Windows 10 Updates, the FOG client will no longer rename the device or ad to AD. If I use an older version of the W10 image - it works flawlessly. This just manifested this past Wednesday.