If you’ve upgraded to Mountain Lion, you might have encountered GateKeeper, Apple’s new security scheme to protect you from malicious apps. In short, GateKeeper expects applications to be “signed” with a security certificate it recognizes and, if not, will keep you from opening the application.

The problem is, a lot of older apps that are otherwise harmless were not signed with an Apple certificate, but the warning makes it seem as if they are problematic anyway. To get around this, you either change the setting in System Preferences to disable the protection entirely (that just takes you back to the way things were before Mountain Lion), or you can get around it on a case-by-case basis.

If you double-click an app that gives you that warning and prevents you from launching it, right-click (or control-click) on the application instead and choose “Open” from the menu that appears. You will still get a warning, but this time there will be a button that will let you launch the app anyway. After that, it won’t ask you again for that application.

To disable the setting entirely, go to System Preferences -> Security & Privacy, and click the General tab. Click the lock at the bottom, left to unlock this pane, then choose Anywhere.

When MobileMe goes away at the end of the month, iDisk will go with it. Before that happens, you should copy any files from your iDisk to some other service.

iDisk is a virtual disk provided by Apple. When connected, it shows up on your desktop as if it were a hard drive, but the files you transfer to and from it are transmitted over the Internet to Apple. The advantage of this approach is that these files do not take up space on your drive and are available from anywhere in the world. The drawback is that it’s slow.

If you’ve never used the iDisk, don’t worry about it as it will be gone soon anyway. Otherwise, a great alternative is DropBox, a free service that provides a type of synchronized disk.

The DropBox software creates a folder on your hard drive that acts like any other folder except its contents are synchronized over the Internet to the DropBox service. If you add the same account to another machine (Mac or PC), the same files will show up there automatically. You can also access the files online through their web site and use it to share large files with others.

The drawback is that it takes up space on your hard drive so it isn’t truly virtual. But it is pretty fast, and it isn’t going away.

Just a reminder that MobileMe comes to an end on June 30. If you rely on it for e-mail or to sync your contacts or calendars between devices, you must switch to iCloud before then. And before you switch to iCloud, you must be running OS X 10.7.x (Lion) on your Macs and the latest iOS on your iPhones and iPads.

If you are using OS X 10.6.8 (Snow Leopard), you can purchase Lion on-line by going up to the Apple menu and choosing “App Store”. Or click here. If you are using an older version of the OS, you will have to upgrade to Snow Leopard first, or buy the Lion thumb-drive installer from Apple.

If you don’t rely on MobileMe for over-the-air synchronization of that data, this really doesn’t concern you. You can make the switch to iCloud, then manually update your e-mail settings if desired.

Note that some services will be lost in the transition from MobileMe to iCloud. Among those, iDisk will go away and there will be no more web hosting. If you need these, you will have to find other services to fill the gap.

For iDisk specifically, I recommend DropBox. For web hosting, I like GoDaddy, but there are a variety to choose from.

If you use Microsoft Word or Excel (or PowerPoint too, I guess), and have recently upgraded to Office 2011, be aware that these apps have an issue with file names that contain a forward slash (“/”).

It used to be that the only character that was “illegal” in a Mac file name was the colon, and that’s because the Mac would use that internally to designate folder paths. So if you had a “Widget” folder on your hard drive that contained the file “gidget.txt”, that path was represented internally as “My Drive:Widget:gidget.txt”.

When Apple moved the MacOS to a Unix base, they had to deal with a conflict. In Unix, the character that designates a folder is the forward slash, so the same file is represented by “/Widget/gidget.txt”. Apple dealt with this conflict by creating a layer above its Unix underpinnings that converts the colon to a slash and vice-versa. Applications could go on using the old-style designation, including slashes, without having to worry about what was going on beneath the hood.

But Microsoft is clearly doing things in a different way. Although it shouldn’t make a difference, the Microsoft apps are having trouble with the “/” in file names, and either refusing to open these files, or opening them as “read only”.

The bottom line is, don’t put slashes into your file names, whether they are meant for the Microsoft apps or not. If you have a file called “Info on 3/5/12.doc”, change it to “Info on 3-5-12.doc” or something similar.

I’m happy to report that the recent iOS 5.0.1 update has made a dramatic difference to the battery life of my iPhone 4. And I’m hearing that from various other sources too about the iPhone 4, the 4S and even the 3GS.

On Saturday morning, I unplugged my phone. Normally, even though my usage was light, I would have expected it to be all-but-dead by Sunday morning. Instead, I still had about 30% charge by the time I plugged it in again Sunday night. I have never had that experience with any iPhone model I’ve owned (this is my third) or with any previous iOS version. I’d say Apple finally fixed a major problem.

Since the battery life issue was the only one that’s been reported about the iPhone 4S, I’d say that’s resolved and, if you’ve been waiting to get one, you can go ahead.

iCloud is the new Apple service that will ultimately replace MobileMe. If you’re a current MobileMe user, you will get all sorts of “reminders” and nudges to migrate to iCloud or start an iCloud account.

Unless you’re running Lion (Mac OS X 10.7) on all of your Macs, don’t do it.

The problem with iCloud is that it requires the latest OS and won’t work with any previous OS for synchronization of data. If you migrate to it and still have a previous-OS Mac, you will lose the ability to share your contacts and calendars among your Macs and iOS devices, and there is no way back.

The alternative is to start a brand-new, free account with iCloud for a specific purpose on your iOS devices (like backing up to iCloud instead of your Mac), but when you do finally migrate, you will have multiple iCloud accounts and, at this time, there is no way to merge them.

The bottom line is, if you use MobileMe and haven’t completely upgraded to Lion, you don’t have to do anything until June 2012 so leave iCloud alone. But if you don’t have a MobileMe account, or have upgraded all of your Macs to Lion, go ahead with iCloud.

A client sent me this neat web site that I thought was handy enough to share:

http://www.downforeveryoneorjustme.com/

Having trouble with a web site and wondering if it’s just you? This site will let you check it and know for sure.

Apple released their new version of the OS today. Lion (v.10.7) is available as a download-only upgrade to Snow Leopard (v.10.6) through the Mac App Store, but you should not even consider upgrading, now or in the near future. Aside from the assortment of problems that are inevitable in any new software release, Lion will not support older, PowerPC-based applications. This means things like Quicken 2007 and older version of FileMaker Pro, 4D, and Microsoft Office (to name a few) will not work and would need to be upgraded or replaced.

There will come a point when you will be ready for Lion, but you should use this time to figure out what will and won’t work and make the necessary changes to ensure the transition will be as smooth as possible. In the meantime, let others work out the kinks.

You can read a review of the new features here.

One of the questions I often get from users of Mail.app results from a less-than-descriptive error message: “Cannot send message using server XXX”. It suggests a problem with your mail server when, in reality, the problem is with the message itself.

The next time you see an error message like that, press the “Edit Message” button, then check all the addresses in the To, CC and BCC fields. If the address is in a blue bubble, click on it to see which address is checked. If you find one that doesn’t look right (no “@some.domain” or similar problem), correct it and try sending again. For example, if you are typing quickly, you might inadvertently address a message to “fred” when you meant to send it to “fred@domain.com”.

If the addresses look right, check the size of your attachments. As a general rule, your attachments shouldn’t exceed 5 MB.

Can’t see an issue so far? Go to your web browser and make sure you actually have a connection to the Internet. Sometimes you will get disconnected for some reason or another, and Mail doesn’t warn you of that.

Finally, call us and we’ll be happy to troubleshoot.

Viruses in the computer world (most of which won’t affect your Mac anyway) have given rise to a new class of malware called “scareware”. In short, this type of app tries to frighten you into purchasing a product you don’t need to fix problems that don’t exist.

Here’s how it works: You’re minding your own business visiting some web site when, suddenly, a page pops up that looks like a standard Mac window warning you of a variety of problems. It urges you to click a link to perform a “free” scan and, before you know it, you’ve installed something you can’t seem to get rid of without paying for it. In short, it’s a hoax designed to separate naturally nervous users from their cash.

Enter “Mac Defender”.

Mac Defender (a/k/a Mac Protector, and probably some other name soon) is just such an application. If you are tricked into installing it, the method for removing it is not obvious. Fortunately, it’s not hard either. You can find detailed instructions with pictures here, but these are the steps:

• Close the Mac Defender window if it’s open.
• Navigate to your /Applications/Utilities/ folder. The easiest way is to click anywhere on your desktop, then go up to the Go menu and choose “Utilities”.
• Start Activity Monitor.app in your Utilities folder.
• If no window appears, go up to the Window menu and choose “Activity Monitor”.
• In the window that appears, look in the upper, right corner and you will see a search box. Type “Defender” there.
• “MacDefender” should appear in the list in the main part of that window. Highlight it and press the red “Quit Process” button in the toolbar.
• Choose “Force Quit” from the window that appears.
• Quit Activity Monitor.
• Navigate to your /Applications/ folder and trash Mac Defender.
• Go to your Apple menu and choose “System Preferences”.
• Click on the “Accounts” icon, then click the “Login Items” tab.
• Locate “Mac Defender” in the list and press the “-” button beneath the list.

To be clear, this is not a virus because it can only get onto your machine with your knowledge and, in fact, your permission. The lesson is, don’t believe everything you see on the web, be skeptical about stuff that tries to scare you into doing something, and be conscious and particular about what you decide to install.