Canon Pixma MP500 Reset PAGE SIZE to A4

Try to perform a hard reset for service mode .

Base on your explainination it seems like, this is because of your setting in MP Navigator, the image may not be scanned properly. In such a case, it is necessary to match the settings in MP Navigator to the document. please do the following. 1) Match the type of the document on the platen glass to the document type set in MP Navigator. For example, when scanning a color photo, select Color Photo in Document Type of MP Navigator. 2) Match the size of the document on the platen glass to the document size in MP Navigator. For example, when the document size is A4, select A4 in Document Size of MP Navigator. (Memo) Auto Detect is set in Document Size as the default.

I could not find a way to do this either Anthony. What i ended up doing was selecting the bottom tray to print from the pc - it seemed to hold the setting for A4 plain paper, whereas the default setting stays at 6x4. A real fault with this otherwise quite cool little printer.
Although, I am having real probs at the moment, the damn thing just wont switch on after we had a power failure in our part of town.
In fact, the entire switch mechanism seems a bit "dicky" all up.
Good luck, hope you find your answer.

your printer CHANGE PAPER TO
A4/LTR/LGL PLAIN
The paper size setting is set to a size other than
A4, letter or legal in fax receive mode.
The paper type setting is set to a type other than
PLAIN in fax receive mode.
Set the paper size setting to A4, letter or
legal and load paper of the same size.
Set the paper type setting to PLAIN.

1-In copy mode, display the Settings screen by pressing "Settings" on the MP500.
2-Select the Setting Tab using the left and right arrows.
3-Select the page size by using the up and down arrow.
4-Select "A4" by using the left and right arrows.
5-Complete the setting by pressing Settings

are you sure it's set to Letter? and not A4 or a diferent size?

The top-loading sheet feeder accommodates approximately 150 sheets (depending on weight), and the front feeder is good for around 100 sheets. Actual media sizes supported by the main feeder (top-loading) include A4, B5, A5, Letter, Legal, Envelopes (DL size or Commercial 10), 10x15cm(4" x 6"), 10x18cm, 13x18cm, 20x25cm, and Credit Card (54x86mm), while the front feeder is less accommodating with just A4, Letter, and B5.

What paper type is set in the driver? ie plain, letter, A4, cardstock?? Also which tray source is accepted. Might try re-setting driver settings to defualt.

There must be s "custom setting" set as default. Check properties and restore defaults where applicable. http://alpha03u.c-wss.com/inc/ApplServlet?SV=WWUCA900 This is an online manual for your machine. Good Luck, Tim

I wonder if it is in fact a printer problem? have you tried different programs?