Installing Snow Leopard on a MacBook that is currently running Tiger

Question

Is it possible to install Snow Leopard on my MacBook that is currently running Tiger? I have heard rumors that Leopard must be installed before Snow Leopard will work. I bought a white MacBook about three and a half years ago with Tiger installed.

Answer 1

1. The Snow Leopard installer itself runs the equivalent of Disk Utility's verify disk step on the volume selected for the install, so while this remains a good idea when upgrading to Leopard or other previous OS versions, doing it as a separate pre-install step is not necessary or likely to improve anything when upgrading to Snow Leopard.
In this respect the installer is quite finicky: if the volume doesn't pass verification, it will refuse to begin the install.
2. Aside from that, the installer is only finicky about two other things regarding format: (a) the drive must be formatted with the GPT (GUID Partition Table) partition scheme (the scheme the drives of all Intel Macs ship with) & (b) the table must conform to the standard GPT format. If the drive doesn't meet these criteria, the installer marks any volumes on it as not suitable for the install & users can't select them.
3. Some users seem unaware of just how different the Snow Leopard installer is from the earlier ones. When Apple talks about streamlining it in the product's blurb, it refers to much more than just eliminating the old Archive & Install and Erase & Install options, notably:
• Unlike the old Upgrade option, SL's version completely replaces the existing OS component files with the ones from the installer's 'payload.' (The old Upgrade option just replaced or patched components that had been changed for that OS version.) This is why the single provided option is equally suitable for a volume that contains an existing OS or an empty one. (It's also why upgrading from Leopard or Tiger works essentially the same way.)
• The new installer doesn't create a "Previous Systems" folder like the old Archive & Install did. There is no reason for this largely redundant folder anymore, since the new installer selectively leaves in place user-added items from the old system folders that they previously had to move back into those folders manually if they wanted to restore their functionality. However, if the "Previous Systems" folder exists because a user did an A&I with an older OS installer, the new one leaves it in place. But since the new OS ignores it, just as previous ones did, this has no effect on OS operation.
• If -- but only if -- users start the install process by launching the "Install Mac OS X" pre-install application while running from an installed OS, that app will use the installed OS's network settings to 'phone home' to Apple's database of software known to be incompatible with Snow Leopard & use that info to decide what if anything to move to a root level "Incompatible Software" folder during the install. The DVD has its own short list, but since that list was created before the DVD was made, it is now out-of-date & incomplete. Thus, it is always a good idea to start the install this way when possible, just as Apple recommends.
• Other minor refinements that only work if there is an existing OS include automatically deciding if Rosetta or Quicktime Player 7 should be installed, automatic language selection for the install process, & enabling the 'install drivers only for local & nearby printers' option. Each of these depends in some way on what's already installed.
4. All these refinements do not make the new installer 100% reliable but they eliminate the most common problems users had with the older ones, especially if they follow Apple's instructions & *do not* erase the drive beforehand. Just as the Installation Guide included on the disc (also available online here) says in the "Advice about installing" section, erasing the drive should be reserved for the rare times when the normal method fails.