I get this error when I try to take my server out of the domain and into a workgroup.
The following error occurred attempting to unjoin the domain "the domain name"
An I/O operation initiated by the registry failed unrecoverably. The registery could not read in, or write out, or flush,
one of the files that contain the system's image of the registry.
I did not set up this server so I don't know what has been done to this thing!