The worst thing a personal computer operating system can do, aside from crashing a lot, is to destroy your data. Indeed, a bug of this sort ought to be a show-stopper, but if you believe all those lurid headlines, such a defect was allowed to remain in Leopard when it was released.

If it sounds frightening to you, you aren’t alone. Certainly, if true, Apple ought to be working like crazy to find a solution, and get it released as soon as possible.

But is this all some new and dreaded defect, or something that’s been a part of the Finder for a while? What’s more, what must you actually do to send your data into oblivion?

Now I wouldn’t recommend that you try this at all, but all you have to do is use a standard Mac OS shortcut for moving files from one drive or partition to another, while deleting the original file. To perform this action, simply hold down the Command key when you drag the file to its new location.

This would seem to be a particularly benign action, and I have little doubt that it works precisely as advertised 99.99% of the time. But what if something happens to interrupt the file transfer, such as a power outage during a thunderstorm, a file share disconnecting from the network, or the target drive crashes?

Well, in theory, the Finder ought to keep the original file intact until the file system confirms that the item has been successfully moved to its new location intact. In fact, that’s how it apparently works on the Windows platform.

However, theories don’t always succeed in the real world. In this case, if something happens to the file on its way to another drive, the original is deleted anyway. So you’re left with a corrupted copy, or perhaps nothing at all!

Indeed, this is a dangerous bug, but it may not be a Leopard-specific defect after all. There are already widespread reports — with apparently enough testing involved — to confirm that this file move issue goes way back to Tiger and perhaps even to Panther. Other reports, which may have less authenticity behind them, trace this particular problem way back to Mac OS 9.

For some reason, it wasn’t discovered or at least confirmed until now, although I fail to see why.

Indeed, wouldn’t it appear at times during Apple’s quality control testing, or was it mistakenly buried in an online bug report, and somehow overlooked? Could it be that it only happens occasionally, even when the proper conditions are reproduced? If that’s the case, it would make it doubly difficult to solve.

I can’t pretend to know what has been going on behind the scenes, only that I would hope that, with the renewed attention to this apparently serious defect, however long it has persisted, it will soon be eradicated. And, no, I am not going to accept those unconfirmed reports that Apple is already testing a Leopard update that contains this fix. Even if true, we don’t know when the rumored 10.5.1 will be out, or what fixes will survive the testing process.

In the meantime, despite the fear-mongering on the part of some members of the tech and mainstream press, none of this should deter you from installing Leopard, assuming the applications you use are compatible. I have gone out on the limb in saying that my particular upgrades — and those performed by people I know — have been universally successful in every respect.

Of course, I use an awful lot of applications, and I’ve found some instances of weirdness here and there, but nothing I couldn’t work around rather easily. The key here is the stability and speed of your workflow. If there’s something in Leopard, or a third-party application, that will cause problems with either or both, then I would suggest you hold off installing Leopard for now and wait for some further updates.

Over the next few weeks, however, you will be hearing more and more about the alleged show-stopping problems in Leopard. Some of that information will no doubt be true. As more and more of you install Mac OS 10.5, you will possibly experience anomalies that Apple couldn’t predict or expect.

It may also be true, as some suggested, that Leopard was forced out of the door prematurely by Apple’s marketing, knowing they had to make good on their promise to deliver the goods before the end of October. One clue that this sort of speculation might be correct is the fact that Leopard went on sale officially almost at the last minute, far closer to the scheduled release date than you might expect.

Perhaps, as some suggest, Apple struggled as hard as it could against its self-imposed deadline to deliver a build of reasonable quality and then declared it Golden Master, knowing full way some features, such as, perhaps, the firewall and a few others, were a little half-baked. In the end, it’s all about money, and you shouldn’t expect Apple to behave any differently.

Meantime, if you’re concerned about suffering data corruption or loss from that apparent Finder bug, take the advice of the doctor in that very old vaudeville joke:

The man says: “Doctor, it hurts when I do that.”

The doctor responds: “Don’t do that!”

In other words, don’t use the Finder’s move command to send a file to another drive. Just drag it over, and when the copying process is done — and only when that’s confirmed — delete the original manually.

Some years back, one of the developers for Mac OS 7.0 told me about a very obscure bug that had been allowed to persist in the operating system. It seemed that something would crash on the twentieth level of a new folder if you did something to it, such as create another new folder nested inside.

Well, I don’t know if they ever fixed that particular oddity, since I don’t know an awful lot of people who bury their stuff that deeply, but I suppose it does happen. So I wouldn’t break out your Classic Mac to see if you can reproduce it, but I’d be curious, I suppose, to hear if you do.

The point of this little remembrance, however, is not to dwell on an insignificant bug, but to explain that they remain ubiquitous in an operating system, even if you and I might regard them as quite stable. In fact, I venture to guess that there are hundreds of bugs in Leopard that Apple has logged.

I am not kidding. The headline is not meant just for show, or to paint a lurid picture on the subject. And, no, I’m not giving you any top secret information. In fact, that number may well well be in the thousands, as it is with any software of this vast scope. But before you rush to remove Leopard from your Macs, or consider sticking with Tiger, let me assure you that this isn’t anything you should be concerned about.

You see, many of those bugs are strictly cosmetic, while others can only be invoked by an obscure set of steps that aren’t likely to happen very often in the real word.

In software development, bugs are traditionally rated in accordance with their potential impact on the user. Indeed, if that bug bites, and it can cause your Mac to crash on a fairly consistent basis — or result in the loss of data — Apple will give it high priority and do their best to get it fixed as quickly as possible. The same is true for any responsible company, and — no snickers please — even Microsoft’s committees will institute crash programs to repair such issues in any of their products.

I said no snickering please, unless it’s just the candy bar!

In any case, bugs of that sort, if they exist, would cause you to see a 10.5.1 pretty quickly, but there are lesser issues that might impact you in a pretty serious fashion. Take AirPort reception, for example. If you can’t get a consistent connection with your home or office Wi-Fi network, or the one at Starbucks, you’re apt to be pretty upset. Indeed there have been reports of problems of that sort and they, too, would require quick fixing.

As I’ve said in my earlier commentaries, I am having difficulty printing documents with Microsoft Word 2004. Indeed, Microsoft’s PR admitted they’re aware of a rare problem of this sort and they’re working with Apple for a solution. Now this might just be some errant line or two of code somewhere that’s causing page ranges to be out of bounds. It may take five minutes to fix, but days to isolate and qualify for release. But it’s surely serious enough to require a pretty rapid repair, and, no, the recently-released Microsoft Office 2004 11.3.9 update did not address this particular oddity.

No, folks, Apple didn’t do anything to deliberately cripple printing in Word. It’s quite true that Office is a sprawling suite with millions of lines of code, and plenty of room for things to go wrong. That they spent a year migrating to Apple’s Xcode ahead of developing Office 2008 indicates that they have a huge amount of work to do even for the simple things. Indeed, it’s clear to me that Apple’s developers and Microsoft’s Mac developers do talk without pulling revolvers and swords. In fact, they are probably quite friendly in the normal course of events.

Naturally, some bugs are of far lesser importance, because there’s a workaround that allows you to avoid them. For example, we use WordPress for content management of this site. It’s easy, convenient and, in fact, has some pretty prestigious users, such as The New York Times.

What I like about WordPress the fact that you can edit your content from any computer with an Internet connection simply by launching a browser and logging in. You can also email your content, but I’d rather take a more direct approach.

However, WordPress and Safari 3 don’t like each other when it comes to writing and editing copy. When you save your document, Safari manages to strip out the paragraph breaks, which isn’t a problem if you prefer one long paragraph, but is otherwise a serious issue. Previous versions of Safari didn’t support the visual editor in WordPress, which puts a simple formatting bar on the top of a page.

Now I realize this particular anomaly isn’t a show-stopper. I don’t know if it’s the fault of the developers of WordPress or Apple and Safari, although I have no problems performing the same tasks in Firefox, Microsoft Internet Explorer or Opera. Moreover, I don’t know whether this requires a full-scale upgrade to Apple’s WebKit, perhaps in a future Leopard update, or it will remain an issue for the people at WordPress to address.

But you see where I’m going. The WordPress issue is probably not considered significant enough on Apple’s end to be worth a high priority, but it is still a bug that someone has to fix. The same is true for lots of other oddities that you might find in Leopard’s performance or appearance that disturb you. There are other defects that are so subtle, you may never see them, or invoke the rare set of concurrent conditions that causes them to appear.

As you can see, when I speak of hundreds or thousands of bugs in Leopard, I might, in fact, be very conservative in my estimate.

Years ago, I would often tell my friends that once they used Macs, they’d never go back. Well, I suppose that was true for some, but others chose to embrace Windows and claimed that it was every bit as good as a Mac and maybe better.

Oh well, I suppose there’s no accounting for taste.

However, it’s also true that, when you become accustomed to something, it may be difficult or impossible to change your ways. Take the Classic Mac OS. Yes, development essentially chugged along until 1999, with the release of Mac OS 9. Aside from some maintenance updates, Apple abandoned it and charged full steam towards delivering Mac OS X. But the first release of the long-awaited industrial-strength operating system upgrade met with a huge amount of criticism about what was omitted and especially what was changed.

The former was easy to understand. In effect, Apple was building a new operating system based on the tried-and-true Unix underpinnings utilized by the NeXT operating system. They were also several years late, and I suspect that the first couple of Mac OS X releases were delivered as much to provide credibility as deliver a robust system upgrade for Mac users.

That didn’t stop people from complaining about various interface decisions, and it really got out of hand in Tiger when Apple’s applications variously incorporated platinum, gray and brushed metal windows. Although it didn’t bother me much, as variety is supposed to be the spice of life, I can see where some folks preferred a more orderly presentation.

That came in Leopard, but the gray/blue-gray motif still doesn’t satisfy everyone, but it doesn’t matter what choices Apple makes.

Now comes the easy part for me: I have no problem with the look and feel of Leopard. I think the Finder windows look just great, and the transparent menu bar doesn’t disturb my ability to use it. I can see where certain types of artwork might cause trouble, particularly if the menu bar is blackened and provides little contrast and visibility for the labels. With judicious selection, however, this shouldn’t be an issue. And with menu bar opaquing utilities already in place, you can get rid of the effect if you choose.

However, maybe Apple should be thinking seriously about putting a slider in the Appearance preference panel where you can make that setting yourself. It’s not as if the system doesn’t provide that capability. That’s how the third parties get it done.

The same goes for the Dock. 3D? Fine with me. I realize that the tiny shaded blue lightbulb-style indicators might seem a poor choice to display which applications are open. You can certainly use a Terminal hack or a third-party system enhancement utility to go back to 2D, and even to change that indicator. But the human eye is an amazing thing. If you give it just a little time, without clouding your mind with prejudgments, you may discover you like it, and that you’ll still be able to detect the open applications without a second glance.

The most important element of a computer operating system, though, is whether it can stay out of the way and let you get your work done. Here Leopard doesn’t disappoint. I continue to run the very same applications I ran with Tiger. Except for the printing oddity with Microsoft Office 2004, where it reports pages as out of range, and the fact that Entourage 2004 doesn’t like Spaces, I’m pleased.

You see, performance is noticeably snappier. That’s a subjective reaction, and it may well be that a benchmarking utility will show little or no change from Tiger, but perceived performance is extremely important. What’s more, Leopard doesn’t crash for me, and the only restarts I’ve done were to install software that required them.

Now I’m realistic enough in my outlook to understand that some of you may have had perfectly awful encounters with Leopard. Maybe you did an Upgrade installation, and confronted that dreaded blue screen of death on the first startup. All right, we know that a third-party system enhancement, most likely an older version of Unsanity’s Application Enhancer, may be responsible. In addition, a Terminal hack in the startup single user mode or a full Archive & Install should exorcise that problem for good.

I also realize that, with thousands upon thousands of possible Mac system configurations, anything can happen and probably will at some point in time. Again, this is nothing unusual, and any of the serious problems will be taken to heart by Apple and repaired, if need be, in a forthcoming system update. Or, if the fault lies strictly with an independent developer, they’ll do what they have to do to be compatible with Leopard if they hope to remain in the Mac marketplace.

As you might imagine, I will be writing regularly on Leopard in the days to come. But with appropriate cautions — and an eye to the compatibility of your applications and utilities — I recommend Mac OS 10.5 without hesitation.

If you believe some of the things written about Leopard in the past week or so, you may consider it the buggiest system upgrade ever! But, as with all things of this nature, that impression is a huge exaggeration.

During Leopard’s first weekend on sale, some two million copies were moved as retail upgrade kits and preloaded on some new Macs. Since then, it’s fair to say hundreds of thousands of additional copies have probably been shipped, and the vast majority of Mac users who have Leopard have installed it.

It’s also a certainty that any point-zero release will have at least some annoying bugs. Some of these issues were pushed aside in the rush to ship the product — though Apple would never admit that. Others were simply not granted a sufficient amount of seriousness, couldn’t be duplicated or weren’t anticipated.

So you can bet that, sometime in the next few weeks, there will indeed be a 10.5.1 update, and that, every couple of months, further maintenance updates will be delivered. This is something you have to expect, and you might feel angry at Apple for not shipping a more robust product, but the fact of the matter is that most of the Leopard early adopters have had excellent upgrade experiences, and I can be counted as part of that number.

Story continued in this week’s Tech Night Owl Newsletter.