Do you have the encryption protocol, e.g., WPA, WPA2 (hopefully not WEP, which is very weak) entered in System Preferences>Network>Advanced next to the Network name, under Security?
Of course, that will solve the immediate issue, but, for several reasons, you may not want to run the computer, including the drive, 24/7, according to the suggestion you have received. That's like saying always stay inside the house in order to prevent ever getting hit by a car, instead of learning how to cross the street safely.
See if there's any other option besides WEP? Did you set up the router with some automatic process? If so, see if you can go back in manually and change that encryption. It can be broken by someone who knows how in a few minutes.
Does your Network Airport pane look like this? Btw, I have double entries for my Network. In case the first one isn't picked up right away, it goes on to the second one. Also, try creating a new location, using the same settings as you currently have.
Be sure "Ask to join new Networks" is unchecked.
Running the computer 24/7 instead of getting to the bottom of this would be a mistake. Not only will you run up your electric bill and waste electricity, but you may be subjecting the hard drive to undue stress, depending on the temperature/climate it is being used in. Besides, something is just not right and this doesn't fix it.
Message was edited by: WZZZ
Had the same issue, belo how I fixed it:
Perform following steps:
Open System Preferences.
Select the Wi-Fi interface and click the Advanced button.
Click the TCP/IP tab.
Click the "Renew DHCP lease" button.
Sleep and wake the computer to test.
Open Keychain Access from /Applications/Utilities.
Remove all AirPort network passwords from the login keychain.
Remove all AirPort network passwords from the System keychain.
Rename the System configuration folder to /Library/Preferences/SystemConfiguration.old. Copy that /SystemConfiguration.old folder to the desktop. Important: Do not move this folder to the Trash, and do not delete this folder.
Restart the computer.
Join the Wi-Fi network. The customer will need to enter their password for their network again, if it requires one.
Now auto joining
very tired of doing this 12 times a day !!! grrrrrr
Not the original topic, but that may be a bit much, indicating that you have the computer set to sleep at quite short intervals. That is not necessary and that will stress the drive because it means parking the heads and then spinning up again rather frequently. I might sleep mine at most three or four times during the day, if that much, and then put it to sleep at night. I also periodically do a complete shut down at night. Of course, in very hot weather here, I might sleep the computer more frequently.
Running 24/7 will also run the fans constantly, among other components, possibly wearing them out prematurely, as well as sucking in more dust, which will reduce ventilation, over time.
If your router can't be set to anything other than WEP, I would consider getting one that can.
Rename the System configuration folder to /Library/Preferences/SystemConfiguration.old. Copy that /SystemConfiguration.old folder to the desktop
I would only do this as a last resort. And you will need more directions for doing this if you choose to try it.
Message was edited by: WZZZ