A.4. The Upgrade Installation
If Mac OS X version 10.0 through 10.4-point-anything is on your hard drive, the Leopard
installer can neatly nip and tuck its software code, turning it into version 10.5.Every thing
remains just as you had it: your accounts, folders, files, email, network settings,
everything-else settings, and so on.
This sophisticated surgery occasionally leaves behind a minor gremlin here and there:
peculiar cosmetic glitches, a checkbox that doesn't seem to work, and so on. If that
possibility concerns you, a clean install is a safer way to go. (A clean install does,
however, require a little more post-installation fiddling to reinstate your settings, notably
your Internet and network preferences.)
If you're still game to perform the upgrade installation, follow the previously outlined
steps 1 through 3. On the Select Destination screen, however, click Options.
Now you're offered several variations of the basic installation. The one you want is
Upgrade Mac OS X. Click it, and then click OK. Proceed with the previous step 4. (The
button described there now says Upgrade, though, instead of Install.)