Camera will not retain time setting

Canon A520 have CR1220 battery as memory backup power. Replace it. It's located at left hand side there is grey rubber cap open it, you will find one more small flap at bottom, gently pull out straight you will see a battery holder remove CR1220 battery replace same type with new one. Normally it lasts for 3 years.

CoolJoe72 only posted one answer, but it was a good one, and it applies directly to you. Check it out here: http://www.fixya.com/support/t313710-having_reset_date_time .

(The short answer is that you need to change the date battery, which you'll find under the terminal cover; it's a CR1220.)

how long has it been since you had it serviced

you may need to take it in to the camera place to get the clock mem batery replaced cos it is out of date

you may need to take it in to the camera place to get the internal batery for the clock replaced also you may need to up load the driver program for the camera

You may want to set the factory defaults by going into the main maenu.

There are two batteries in the camera. One is the big one you charge and the other is a little coin type battery. This coin battery maintains your settings and when it goes your camera forgets things. Same setup on computers and a lot of other electronics. In your camera the battery is a CR1220 worth about $1-$2. It should last about 3-5 years but you never know.

The battery is in a little holder on the left hand side of the camera. Its under the same cover as the usb connector and power plug in. You should be able to pop out the battery holder fairly easily. This is one of those things that if you take the camera to a battery store they will probably do it for you if they aren't busy. If you look at page 137 of your manual you will find the instructions for doing it yourself.

You have to change the 'date battery'. Use the user manual to find its location.

Mine is Canon A520, located beside the cable link sockets. Battery is CR 1220.

We have a Canon A520 and it was having all the symptoms noted. Searched for a resolution on numerous sites including the Canon Support site. While on the Canon Support site, I found an FAQ on "How to RESET the A520". Turn camera on, find and hold MENU button for 5+ seconds until "Reset settings to default?" screen appears. Arrow over to OK and press the SET button. When we did this the battery low indicator showed, replaced batteries with standard alkaline batteries. Everything functions properly, with no additional problems for the past 5 days. I guess the camera just lost its mind and had to be defaulted and rebooted, hope this helps.

Solution: Replacing the date battery PowerShot A510 and A520

Replacing the Date Battery If the Date/Time menu appears when the camera power is turned on, the date battery charge is low and the date and time settings have been lost. Please purchase a lithium coin battery (CR1220) and replace it as follows.
Please note that the first date battery may appear to expire relatively quickly after you purchase the camera. This is because it is installed in the camera at the point of manufacture, not when you make the purchase. Be particularly careful to keep the date batteries out of the reach of children. Seek medical assistance immediately if a child swallows a battery since corrosive battery fluids could damage the stomach or intestinal wall.

1. Confirm that the camera is turned off.
   
   
2. Open the terminal cover and use your finger nail to pull out the battery holder.
   
   
   
   
3. Pull open the battery holder in the direction indicated by the arrow (1). Remove the battery by pulling it up in the direction indicated by the arrow (2).
   
   
   
   
4. Insert a new battery with the ( ) side facing up.
   
   
5. Replace the battery holder back and close the terminal cover.
   
   
6. When the Date/Time menu appears, set the date and time.
   
   

After purchasing the camera and turning on the power for the first time, although the Date/Time menu will appear, you do not need to replace the date battery. If you ever dispose of your camera, first remove the date battery for recycling according to the recycling system of your country.