We still recommend only one System Folder per volume. We are aware of some potential risks involved with multiple System Folders on one volume. They are:
* Confusion - It is very easy to become confused, either for the user or
for a third party application, with the presence of more than one System
Folder on the hard drive.
* Disk Cache - In rare instances, information in the Disk Cache may not
get written to the hard disk before restarting. If you were blessing a
System Folder before restarting, then your Macintosh may not recognize
that it has a System Folder.
* Hard Disk Problems - In some instances, users have experienced low level
hard disk directory problems, which were heightened by having multiple
System Folders. In these cases, a Macintosh typically tried to load
Extensions, Control Panels, and Preferences from an unblessed folder,
and not from the blessed System Folder.
* Third Party Utilities - Third party utilities for blessing or unblessing
multiple System Folders alter information in the hard disk directory's
boot blocks. This is not supported by Apple and may cause problems.
If a user, for whatever reason, needs to have multiple System Folders, it is critical that the other System Folders be deblessed correctly, as follows:
1) With System 7.0 and later, move the System file to the Preferences
Folder (hiding the System file in this way deblesses the System
Folder).
2) Close the System Folder and verify its state before restarting. A
blessed System Folder has a Macintosh in its icon. A non-blessed System
Folder does not.
3) Rename the deblessed System Folder to any name other than "System
Folder".
Article Change History:
09 Dec 1994 - Complete rewrite of article.
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