The Server component always uses the Local Machine hive in the registry, which is always available.
The user credentials used to start the process can be the Local System Account, a local user, or a domain user. Only local users (or domain users that have previously logged on to the Server machine) have a current user hive; others use the default user hive, HKEY_USERS\.DEFAULT, instead.
When using the default user hive, any changes are only cached in memory for use by the process, and are not recorded to the registry. Also, you cannot make the default user hive your current user hive if you log on to the interactive desktop for the Server.
While this is not a problem for the Server processes, this may be problematic for registry settings needed by the DBMS. For example, Informix® requires certain registry settings that are recorded in the current user hive for the user logged on at the time that the Informix utilities are used (SETNET32). To correct this issue, once you set up the options, you can copy them to the default user hive using the REGCOPY utility. You must re-run the REGCOPY utility each time you change the options.