These Quick Checks won't usually fix your problem, but may help you figure out what the cause is. Telling us the results of these tests can greatly speed up your diagnosis and solution.
Login as another userMany of the problems you are likely to have are due to files, often corrupted in some way, that reside in your Home directory, especially its Library folder. To determine if such a file is the cause, you can log in as another user, ideally one that has never been modified from its initial default state. If the "pristine" user account does not have the same symptom, it's a sure sign that the cause is some file in your account that was added or got corrupted.
To perform this check, you need to have an additional account. To create one, if it does not already exist:
Now, from the User menu, which should be in the upper right corner of the menu bar, select the name of the newly created user. Log in. Test to see if your problem still occurs and note the result. Log out.
1. Launch System Preferences and select Accounts.
2. At the bottom left of the window, click the + button. Fill in the needed blanks (for a name and password).
3. Still from the Account System Preferences pane, click the Login Options button. Make sure the checkbox that says "Enable fast user switching" is enabled.
If the problem does not occur when logged in as a different user, it means something in your Home directory is causing the problem. Often, the culprit is a preferences file. The solution is to remove the file. At this point, you can try to figure out on your own which file is the culprit (and what to do about it), or sign up for a consulting session for additional assistance.
Re-login with login items disabledLaunch System Preferences and select Accounts. From the list on the left, select your own account. From the row of buttons that appear to the right, select Startup Items. If you have any items listed here, they are a potential source of trouble. To determine if this is the case, you can login with startup items disabled. To do this:
1. Select Log Out from the Apple menu.
2. When the Login window appears, enter your name and password.
3. Hold down the Shift key and click to log in. Continue holding down the key until the desktop items begin to appear.
Now check to see if your problem still remains. If it is gone, it means that a startup item was the cause. At this point, you can try to figure out on your own which one of the items is the culprit, or you can sign up for a consulting session for additional assistance.
Do a safe bootA safe boot is most useful if you are having problems starting up your Mac. It disables certain files on your Mac that may be interfering with a successful startup. When running a Mac from a Safe Boot, you may be unable to connect to your network or use connected FireWire and USB devices -- but at least you will have succeeded in completing a startup.
To do a Safe Boot, start by turning on your Mac. Press and hold the Shift key down immediately after hearing the startup chimes. Continue to hold down the Shift key until the words Safe Boot appear on the blue screen. That's it.
When doing a Safe Boot, the Mac automatically performs disk repairs, similar to what happens when you select Repair Disk from Disk Utility. The advantage here is that you do not have to locate and startup from the Install CD to get this to work. This alone may fix your problem. That's why it pays to restart normally immediately after a Safe Boot. If you can now startup successfully, your problem may be fixed! Otherwise, one of the files that got disabled is the likely cause of the problem. Unless you are familiar with these files and how to fix problems with them, you may be better off signing up for a consulting session for additional assistance.
If even the Safe Boot fails to get your Mac to start up, and especially if you hear a sound other than the normal startup tones, either you have a serious software problem (which may require either a complete reinstall of Mac OS X and possibly an erasure of the entire drive) or you have a hardware problem. To check for hardware problems, you can run the Hardware Test software that came with your Mac. It will either be on a separate CD or included on the Install DVD (depending on the Mac model you have). If you need help in doing this, we suggest you sign up for a consulting session for additional assistance.