Service ADsync was not found on computer

Earlier, I logged in to my tenant and noticed that a couple of users that I had created yesterday on on-prem did not replicate to Azure AD.  I checked the directory sync status and sure enough it had not synced.  I opened Azure AD Connect and received this:

An error has occurred on the Root page preventing Azure AD connect from continuing.  To protect existing data, the wizard must be close.


Service ADsync was not found on computer… The first thing I did not do was exactly what it said, to contact Microsoft.  The next thing I did was uninstall AD Connect, but then I had issues reinstalling (Maybe I should have called but I was impatient).  I tried removing the windows folders and using a registry cleaner to no avail.  Then I searched through the registry, found and removed everything I could find, then I was able to reinstall and configure successfully.  The whole process took about 45 minutes to figure out, but I dug into it and found that by removing two keys in the registry it would have worked and I could have saved myself a few minutes.  The key names vary but the

product name will be “Microsoft Azure AD Connect Health agent for sync” and “Microsoft Azure AD Connect synchronization services” located here in the registry.


Look for product name: Microsoft Azure AD Connect Health agent for sync and delete the whole folder (the name will be like B653466B76163DC4D8F918CE1F7B4620).

Look for product name: Microsoft Azure AD Connect synchronization services (the name will look something like B653466B76163DC4D8F918CE1F7B4620).