Be Safe, Install (System 7.5) Clean

Normally, whenever you upgrade your machine with new software, the existing versions are overwritten by the new versions that you are installing. And why not, since we all want the latest and greatest version of the various software applications that we have on our computers. Unfortunately, in this less than perfect world we live in, sometimes things go wrong and sometimes the newer versions don't work better than the version we already had, or they work differently in a way that we don't like, or maybe they don't work at all, or maybe they even crash our machine. When the new version that we are trying to install is the Macintosh system software itself, problems can be especially frustrating and hazardous since we can sometimes get ourselves into a state where the machine doesn't even start up anymore. Then I get an anxious telephone call and the voice on the line pleadingly asks, "How can I just get back to what I had before?". There is some good news on this front that I have mentioned briefly in previous editions of Omnibus. Many of you have asked for additional information.

Starting with System 7.5, users can now perform what is called a "clean install" of the Macintosh system software. So instead of overlaying your existing System Folder contents with all new software and taking your chances that everything will work as you hope, you can now create an entirely new, separate System Folder and leave the current System Folder (and its contents) untouched. Then you can try out the new version of the system and see if everything is to your liking. Switching back to what you had before is quick, easy, and most important, painless.

As you know, a normal system software installation modifies and updates the existing online production version System Folder. A clean installation on the other hand, disables the existing System Folder, leaving all files in place, and forces the system Installer to create a new separate System Folder. In order to do a clean install of System 7.5, follow the instructions below in the order presented.

System 7.5, and the System 7.5 Update (see MacOS) are available on the ASHD server.

If you have a Disk Tools Disk:

1. Shut down your computer.
   
   
2. Insert the Disk Tools diskette into the floppy drive, and turn on the computer. At the desktop, the Disk Tools floppy disk's icon should be in the upper-right corner of your screen with your hard drive's icon below it. If the computer ejects the Disk Tools disk, make sure you have an Apple SuperDrive (formerly FDHD) that will read high-density disks and that you are using the Disk Tools that came with your copy of System 7.5.
   
   
3. Run the Disk First Aid application. Disk First Aid can detect and repair problems with a hard disk.
   
   
4. Select your computer's main hard drive's icon at the top of the Disk First Aid window.
   
   
5. Click on Repair. Disk First Aid will check your hard disk for any potential problems and will attempt to fix them if necessary.
   
   
6. Repeat this procedure for each hard disk attached to the system.
   
7. When you're finished verifying the hard disks, choose Quit from the File menu to return to the desktop.
   
   
8. If Disk First Aid can't repair a hard disk, you should back up the hard disk and re-initialize it using the appropriate formatting utility for the drive in question. For Apple drives, use the Apple HD SC Setup utility.
   
   
9. Next you should update the Hard Disk Drivers on your hard disks so that they may be compatible and perform better with System 7.5. If you don't have an Apple hard drive, or you use third-party software to format your hard disk, don't use the Apple HD SC Setup utility (it won't recognize your hard disk anyway). You should, however, contact your hard drive vendor to verify that your formatting software is compatible with system software version 7.5. If you have an Apple hard drive, you should update the drivers with the version of Apple HD SC Setup that's on the Disk Tools disk, following these steps:
   
   • Double-click the Apple HD SC Setup icon on the Disk Tools disk.
   • Click on the Update button.
   
   When you're finished, click Quit to return to the desktop.
   

   Sometimes HD SC Setup can't update the hard disk driver (indicated by a "dimmed" Update button). Here are some possible causes and solutions:

   • If a third-party utility formatted your hard disk, you should obtain the latest version of the utility to update your hard drive.
     
     
   • If a version of Apple HD SC Setup more recent than the version on the Disk Tools disk formatted your hard drive, don't update the hard disk drivers.
     
     
   • Your Macintosh has an internal IDE drive. Currently, this only applies to the PowerBook 150 and Macintosh 630 family computers. Skip this step unless you have a second Apple SCSI hard drive.
     
     
   • If an earlier System 6 version of Apple HD SC Setup formatted the drive, it may not have left enough room for the updated driver. You don't have to update the hard disk drivers. However, if you intend to use file sharing or have a Macintosh that can use virtual memory, then you need to back up the disk and re-initialize it with the current version of HD SC Setup. This erases the disk, so be certain you back up the hard disk first.
     
     
   • If the driver is corrupt, the Macintosh doesn't recognize the drive (that is, the drive doesn't show on the desktop when you start from a floppy disk). You may wish to re-initialize it with HD SC Setup. This erases the disk, so be certain you back up the hard disk first.
     
   
   
10. Check the available hard disk space by opening the hard disk's window and selecting by Icon" in the View menu. The amount of available disk space appears in the upper-right corner of any open window. To install System 7.5 with PowerTalk and QuickDraw GX, you should have at least 21MB available on the hard disk where you plan to install the system software. (I don't recommend installing either PowerTalk or QuickDraw.) Installation of just the base operating system requires approximately 14MB of drive space. If there's less than the required space available, you'll need to delete some unnecessary files by moving them to the Trash, or copying them onto floppy disks or other media before moving them to the Trash.
    
    
11. Install System 7.5 by choosing Shutdown from the Special menu. The Disk Tools will automatically eject.
    
    
12. Insert the "Install Disk 1" disk into the Macintosh and turn the computer back on again. The computer will start up with the system files on the Install disk.
    
    
13. Once the "Welcome to System 7.5" message appears, click Continue.
    
    
14. When the installer window appears, press the Command-Shift-K keys simultaneously (the Command key is the key with the Apple and the 'Cloverleaf', just to the left of the space bar.) You will be presented with a small dialog box with two selections:
    • Update Existing System Folder
    • Install New System Folder
    For a clean install, select Install New System Folder and click "OK." Make sure the Destination Disk on the bottom left is the disk you want to install on, then click Clean Install on the bottom right. This will install a new system folder and rename your current System Folder to "Previous System Folder."
    
    
15. Insert the other disks when the Installer instructs you to.
    
    
16. Note: After performing a System 7.5 Clean Install, when About This Macintosh is selected under the Apple menu, it no longer displays the specific Macintosh name. Instead, it displays only "Macintosh", "Macintosh Powerbook", or "Power Macintosh" depending on which system it is running on. If System 7.5 is installed over an existing system (pre 7.5), it retains the specific Macintosh name for the About This Macintosh window. This holds true for future Macintosh computers also.
    

A clean install of System 7.5 is now complete. You should restart your machine and verify that it comes up correctly and all your applications work before you make any modifications or add anything to the new System Folder. Then you can slowly (one-at-a-time) reinstall the non-standard 'vanilla' Apple system items from the old System Folder (now named "Previous System Folder") such as fonts, screen savers and device drivers. Note: If possible, you should reinstall these items from their original disks. If the original disks are not available, you may move the non-standard items from the Previous System Folder to the new System Folder. Be careful not to replace anything that's already in the new System Folder. Only move items that are not already in the new System Folder. The best way to do this is to open each corresponding folder within the System Folder and the Previous System Folder and then compare the contents. Move anything that isn't already in the new System Folder and its sub-folders, from the Previous System Folder and its sub-folders. Then restart and check out your Macintosh after each move to make sure there isn't a compatibility problem. Any system extensions or control panels installed appear as icons across the bottom of the screen when you restart. They load into memory at startup time and modify the standard behavior of the operating system. If the Macintosh fails to restart or behaves erratically, you probably have an incompatible or conflicting INIT (also known as a system extension or control panel). To verify this problem, follow these steps:

1. Restart, and after you see the picture of a computer with a smile, hold down the Shift key.
   
   
2. You may release the Shift key when the "Welcome to Macintosh, Extensions Off" message appears.
   
   
3. When the Macintosh is ready, try to recreate the erratic behavior.
   
   
4. If the problem no longer occurs, then you have a conflicting extension or control panel. Continue with the steps in the next section in order to isolate the incompatible or corrupted INITs in the System Folder.
   
   
5. Open the Control Panels from the Apple Menu. Double click on the control panel called Extensions Manager.
   
   
6. Go to the pop-up menu that says All On and pull it down to System 7.5 Only. This will disable all non-standard extensions and control panels. You will notice that the other items no longer have a check mark by them. Close the Extensions Manager.
   
   
7. Go to the Special menu and choose Restart.
   
   
8. Attempt to recreate the problem.
   
   
9. If the problem doesn't occur, use the Extensions Manager to enable another extension or control panel and restart the Macintosh. Note: You can enable items in the Extension Manager by simply clicking on the name of the item so that a check mark appears.
   
   
10. Attempt to recreate the original problem. Repeat the appropriate steps above for each item listed in the Extensions Manager until the problem recurs. The last item returned to the System Folder is probably the cause of the problem.
    

Finally, verify that your applications are performing normally. If not, refer to the application manual or contact the vendor. If you still cannot succeed in getting the applications to work correctly, you still have the original system folder on your machine. By using one of the system switchers or system picker application, you can choose to restart with your old System Folder. That's the beauty of doing a clean install.

(Note: Some of the material for this article was extracted from the Apple Technical Information Library, Apple's official technical support database.)

If there are things that you would like to see discussed in this column in the future, please send your suggestions (as well as any comments, questions, or complaints) to Peter Furmonavicius

Peter Furmonavicius is a senior research programmer for C&IS Technology and Planning.