How to fix the error on Mac OS xcron?

Sometimes when I'm working on my laptop and try to empty the Recycle Bin Mac OS X, it happens that I get a message saying "Could not complete the operation because the item is in use XXXX" (XXXX would be the name of the file in question).
This is especially frustrating because most of the time that has happened to me the truth is that the file has not been open, not even the application has been running for that document.
This is a bug in Mac OS X that Apple has not corrected. In most cases can be solved simply select the "Secure Empty Trash ..." from the Finder menu operating system. But if this fails, there is a trick that you can apply, and that you explain after the jump.
Launch Activity Monitor, an application of which I have already spoken. To do this you can enter the name of this app in the Spotlight search, or you can go to the Applications folder and then the Utilities folder.
Inspect the top field says "All processes" and not "My Processes". Go down to a process called Locum, seleccionadlo and make click on the button "Quit Process".Now you can try again to empty the Recycle Bin.
On occasion we may occur sporadically when starting your computer that we see a message like "no bootable device - insert boot disk and press any key"
Well let's see the steps that we must continue to address this problem. The first thing to do is restart the computer and hold down the Alt key We'll have different boot options. We will see the Mac OS X volume, if you click on it, we can boot the computer, the problem is that the next time you restart will have the same problem.
To solve it we must do is start pressing the Alt key and then select System Preferences and select the Startup Disk icon.In the list that appears select the option hard disk and the name of Mac OS X 10.6.x. With this simple change the computer boot properly next time.