Procedural differences between 'updating' and 'upgrading'

JimmCMPIT and macjack,

Many thanks for your advice. I was already of the growing view that it was more sensible to disconnect external drives and other peripheral kit when doing an OS upgrade, but I just wasn't certain whether it was absolutely necessary. Perhaps another important aspect of it is that, because upgrading is something that we all don't do that often, it's easy to forget to disconnect all such devices when the time comes?

In Stage 6 you state that the installer automatically goes into the Applications folder. Does that only ever happen with OSX upgrades? (On this particular machine, I've not done an upgrade to OSX as yet). I ask because updates (as opposed to upgrades) never seem to temporarily go into the Applications folder, or anywhere else where you can get at them (not that I'd personally want to). Instead, they always seem to bypass any such arrangement. The same happens with apps downloaded from the Apple Apps Store. I find that it's only third-party apps or utilities that obey my setting in Safari and deposit the dmg file on my Desktop, thereby allowing me to preserve a copy of the installer, and thence of the app.

Macjack,

That roaringapps website is very useful indeed, so thanks for telling me about it. (You got the URL slightly wrong, BTW). The listings I found there have helped firm up my suspicions that if I were at present to upgrade to El Capitan I'd lose my two main applications, ones that are essential to my daily work. They were bought only a year or so ago and cost me an awful lot of money. A third and quite crucial app of mine, from Adobe, was purchased from the Apps Store but suddenly stopped working altogether six months later - on the very same edition of OSX! To this day, it fails to even launch. I've felt quite cheated about that one. It seems that, under the premise of incompatibility, Apple have the power to effectively pull the plug on any app at any time.

What about device drivers? Do you have to reinstall device drivers when doing an OSX upgrade? For example, for a printer or a scanner?

What basically happens during the upgrade process itself? Does the Installer automatically wipe the existing OSX partition before then applying the new edition of OSX, or is the downloaded software merely installed over the top of the existing OSX, warts and all?

On the matter of device drivers still, suppose you find a suitable driver, install it, but then discover it fouls everything up. How do you go about uninstalling that driver? Doubtless, the driver will be split up into many different files that'd be spread around OSX in folders such as Library, Users, etc. In a case like that it'd be inordinately difficult to locate and delete those files individually, so surely instead it'd be best dealt with by going back to the last good state of the whole OSX partition (say, just before you installed the driver)? If that's so, then how exactly would you do that? Would you have to use TM in some special way, or is there a means inside Disk Utility to do it?

Thanks. That link's very useful. I've printed off a copy of that page, to keep to hand in case I ever get into that situation. Many times I've searched for an article like that on the Apple website but never found one.

It's about Mountain Lion but I suppose the same procedure would apply to Mavericks, Yosemite and El Capitan.

Actually, yesterday I found at Epson's european site an OSX driver for a scanner of mine (hitherto used on a Windows machine). It listed two different kinds of driver, though, and I can't fathom why. I'll have to start a new discussion in these forums and ask if someone can provide an explanation.