Q: After upgrade to maverick I'm not able to preview my pictures and download images. Please advise

Hello Daing Alwee,

Thanks for using Apple Support Communities.

For more information, take a look at:

OS X: What is Safe Boot, Safe Mode?

http://support.apple.com/kb/HT1564

Starting up in Safe Mode

To start up into Safe Mode (to Safe Boot), follow these steps.

1. Be sure your Mac is shut down.
2. Press the power button.
3. Immediately after you hear the startup tone, hold the Shift key.
   The Shift key should be held as soon as possible after the startup tone, but not before the tone.
4. Release the Shift key when you see the gray Apple logo and the progress indicator (looks like a spinning gear).

Have a nice day,

Mario