Note: The problem discussed below behaves differently depending on the type of email account being used. Users of POP mail accounts are indeed noticing a problem with deleted email messages appearing in Spotlight search results. Please see this post for updated information.

Our friends over at Engadget have highlighted a Cult of Mac post that, at first glance, appears to have found a bug in Spotlight's caching of email search results on the iPhone. The idea is that after you delete an email from your inbox in the iPhone's Mail.app client, you can still locate and open the e-mail using Spotlight search, if you know the subject of the message.

What's really happening, though, is what Apple might otherwise call "user confusion." When you delete an e-mail message in most mail clients, the message isn't magically deleted, but instead moved to a "trash" or "deleted messages" folder. Being a folder, it is indexed by Mail to provide an unread count, as well as by Spotlight so that you can easily find messages in the folder. When you search for the email, it shows up in Spotlight and opens in Mail because the message still exists in your trash folder.

All right, so what can you do to avoid this? Well, you need to empty the trash folder from your email. With many providers, you can just go to the trash folder, and delete the message from there to permanently remove it. The problem there is that, if you use a service like Gmail, the message doesn't really get deleted when you do this because of the way Gmail translates its labels into folders. Gmail's Trash folder is also set to purge itself after 30 days by default.

Your options? You either have to use the Gmail web interface in Safari, or if you don't mind tweaking your Gmail settings, you can enable the Advanced IMAP Controls Lab and then change your Gmail settings to immediately delete messages instead of using the trash folder. (Note that if you have your "All Mail" label configured to show up in IMAP, you will need to either disable it, or delete the message from that folder on the iPhone as well. See this thread for more information.) Once you've deleted the message, go in to the Trash folder and hit the refresh button to ensure that the message is no longer listed, which will remove it from the local mail cache. This should also clear up Spotlight's index so that the message no longer appears.

By now, you're probably wondering if this is really something to worry about. In my opinion, it really depends on how you manage your email. If you rarely delete messages, or you just delete things that are not of interest to you, they will most likely disappear from your trash folder after a specified time period that is set by your email provider (usually somewhere between 7 and 30 days.) However, if you intentionally delete messages with the idea that the message is unretreivable, then you should probably consider testing this out for yourself to see if it affects you. Again, with many providers, just periodically deleting the contents of the trash folder will do the trick. If you use Gmail, or your company's email services are hosted by Google, then you may need to log in to the web interface periodically to empty the trash, or you can look into the available configuration options, if you feel comfortable doing so.

So in reality, this isn't really a bug as much as it is what I would call "intended, but unexpected behavior." Many people simply forget that the trash folder exists, particularly on the iPhone where you don't always see it sitting off to the left hand side of your inbox. Checking your trash folder for any unintentionally deleted items, and cleaning out the old messages periodically, isn't really a bad habit to get into. With that said, however, I do think that Apple could improve this behavior by implementing some simple changes like adding an "Empty Trash" button to the trash folder, showing the count of all messages in the trash instead of just unread messages (so that it's easier to notice there are messages in there), and having Spotlight either ignore deleted messages like Leopard's Spotlight does, or at least indicate that they were found in the trash.

What are your thoughts on this? Do you consider this to be a bug, or do you think it's just a place that Apple could improve the experience on? Let us know in the comments!

Update: Leander Kahney has posted an update to the original Cult of Mac post that clarifies this issue a bit more. It seems that accounts using POP are configured by default to remove messages after one day or one week, thus causing them to continue to appear in Spotlight search results. Unfortunately, there isn't an option to remove them immediately, however, only after a day, one week, one month, or never. Because of this, Spotlight still sees them in the index, and Mail still contains a cached copy of the message until the time limit configured in the settings is reached.

If you'd like to check out this setting for yourself, go to the Settings app, tap on Mail, Contacts & Calendars, and choose the POP mail account you want to modify. Scroll down and choose Advanced, and the retention settings will be at the top of that page under Deleted Messages. It appears the default for a new account is to retain messages up to one week. So this is still the OS doing what it's configured to do, but there really should be an option to remove messages immediately here. If Apple were to add an option there, and/or remove Spotlight's ability to index deleted messages, the problem would be solved.

Update 2: After further investigation, it appears that some messages deleted on POP accounts do disappear from Spotlight, while others show up long after the message is deleted. I have conducted several tests on this situation, including on different versions of the iPhone OS, and have posted an update with details.

Today is Data Privacy Day, a global initiative to highlight information security rights and practices, especially among teens, professionals, corporations, and the government.

As part of the celebration, TUAW (along with our sister blog Download Squad) has seven good ideas for you about how to keep your data safe and away from prying eyes with Mac OS X Leopard. Also, be sure to browse TUAW articles filed under Security for other tips and alerts about keeping your data safe.

1: Turn on your firewall

Leopard, as we all know, comes with a built in firewall to prevent other computers from connecting to internet-facing ports on your computer. But: Did you know it's turned off by default?

To turn on your firewall, open System Preferences, and click the Security icon. Then, click the Firewall tab. Make sure either "Allow only essential services" is selected, or you can choose to "set access for specific services and applications" yourself.

You can also use "Stealth Mode": when enabled, computers that send data to blocked ports won't even get acknowledgement that the data was received. To enable Stealth Mode, click the Advanced button on the Firewall tab of the Security preference pane, and click the check box next to "Enable Stealth Mode."

2: Set a screen saver password

A feature popular with Windows users, Mac OS X can also lock your screen when your computer sleeps or when the screen saver comes on. Simply open System Preferences, select Security, and choose the General tab. Click the check box next to "require password to wake this computer from sleep or screen saver," and you're all set.

If you have automatic login enabled and click the "require password" check box, Mac OS X will recommend that you disable automatic login. This means you'll have to enter your password to turn your computer on, too; nefarious nogoodniks won't be able to restart your Mac while the screen saver is on to circumvent the need for a password. Good thinking.

Have you ever tried to empty the Trash on your Mac only to receive a dreaded message that said the trash couldn't be emptied because a file was in use? Well, "What's Keeping Me" hopes to solve this problem with it's advanced trash-error detection technology (we kid, it's really just magic).

If you encounter the message that the trash cannot be emptied, just click on What's Keeping Me to see what application or process is keeping the trash from being emptied. You can have What's Keeping Me quit the application or if need be kill (force-quit) the application.

You can download What's Keeping Me from HAMSoft Engineering; this application is freeware, however, donations are accepted.

Update: Alas, it looks like I'm going to have to withdraw this one. Do not use this tip, particularly on PPC Macs. Although it worked fine in my initial testing on an Intel Mac, it's becoming clear that this doesn't work for everyone, nor does it persist after a restart. So while I don't think it's dangerous (if you tried this and it didn't work properly, just force-restart the Finder to return things to normal), it is not actually a good solution. See our earlier Ask TUAW post for other, more permanent ways of doing this.

On an older Ask TUAW we were asked how to add the Trash to the Finder sidebar. I pointed to several different solutions to this, but just recently reader DG left a comment on that post with far and away the most elegant solution. Basically, show the Trash folder in the Finder by clicking on the Trash can in the Dock. Next hit ?-i to reveal the "Trash Info" window (right). Click on the triangle to reveal the Preview if it's not already visible and then drag the preview icon onto the Finder sidebar and drop it.

This will place the Trash in the sidebar with the proper icon and you can now drag and drop files to the Trash from the Finder. Not only that, the icon will even animate to show whether the trash is empty or not (though it may take a few moments to refresh your Finder window so you can see it).

Thanks, DG!

It's time yet again for Ask TUAW, our weekly questions and answers column. This week we'll be tackling questions from last week about putting the Trash in the Finder sidebar, problems with Mail, keeping track of Books, and more. As always, please leave your own comments, and ask more questions for next week either in the comments to this post or using the tip form. Now let's turn to this week's questions.

I found this OS X trash primer over at YouTube in the new video listings. For many of you readers this is going to be old news--how to throw away locked or busy files--but for those of you who are new to OS X and the Macintosh, you may appreciate the basic how-to steps that the video offers. You don't actually need a third-party product to dispose of an application, but many OS X users like to keep their systems clean and tight.

It seems like today is Apple portable pain day. Nathan Makan sent along this picture of his MacBook Pro that sadly died. I assume that Apple replaced it for him, but still his MacBook Pro was so young.

This is just fantastic. French artist Invader creates mosaic sculptures of images from pop culture using the Rubik's Cube as his medium. Called "Rubikscubism," his works include a classic Mac trash can and, my personal favorite, the pre- and post-representation of a defragmented hard drive (pictured at right). Other sculptures include Space Invaders characters, Nintendo's Mario and a very Nintendo-like explosion.

Here is a Flickr site of a recent Rubikscubism gallery opening, and here is the artist's Flickr page. If only the Rubik's Cube had been given an aqua colored side...