Fax memory My Canon MP830 all in one is stuck. The fax memory is always on and it says "Memory in use:10%". How do I erase this,since this is stopping any faxes from coming in.

This thread might be dead but I found that you CAN turn off report printing, which also frees up the memory, in the Fax->Menu->Maintenance/settings->Device Settings->Fax Settings->TX Settings->TX Report. Turn reporting off and it clears memory also. Hard to find but its there.

OK I FINALLY FIGURED THE SOLUTION FOR THIS MAJOR PROBLEM ON THE MP830
Here's our / your situation nightmare - the screen says 40 or say in my case 100% memory full and there is NO way you can fax right?  or scan another fax adf into memory to send.  You are pulling your hair out????  that was me - actually I was just about to SMASH THIS MACHINE and NO THANKS to Cannon for zero help on their website - except pushing more of their products every time I typed mp830 how to clear memory - that should be #1 on there FAQ!!!
Answer you HAVE to print ALL reports - I usually don't want to because it wastes paper and I always hit the stop -  why do I need to print the report - I have two eyes - I can SEE the fax didn't go thru - Duuuuuuuuuuuuh  - this happens when say a fax doesn't go through or wrong #.  Now in the past on ALL faxes you can / could turn this option function off.  THANKS CANNON for making it not possible - ooooooooh  Yeah you waste a ton of ink on all of these stupid not needed reports - why you might ask? 
let's say your fax like my situation has 100% memory full - that means I have 10 reports in memory (which I had zero idea about) -  each report amounts to 10% of that memory - that thanks to Cannon they MUST be printed before I can use it again! 
That's lame & NOT GREEN  SHAME on you Cannon - meaning I have to wasted ALL that ink and paper on something I don't want to waste or print!  but NOPE you don't have that option - that's crazy!!!   I looked far and wide to find another solution - and no as the many cooky solutions I saw on this site or others DON'T WORK - turning your fax on and off and unplugging it doesn't work... NEXT
isn't that wonderful!!!  I can only imagine my fellow readers of this who been FREAKING out for days on end (like me!!!)  how to fix this - and zero help.   Nightmare city
On my previous fax machines I owned  you had the option to turn printing reports off.  Nope not on this Cannon - to my knowledge and research - so let's waste more paper and spend tons more on the already WAY over priced ink!  Shame shame

Try this first: Reset the device when it does not respond. If the device does not respond, disconnect and then reconnect the power cord. At the device or at the electrical outlet, disconnect the power cord or adapter. Wait approximately ten seconds and then reconnect the power cord. Wait until the device has completed its cycling process before submitting another job request.

You can print and delete faxes from memory: 1.- Make sure the FAX button is lit (press it if not) 2.- Press Menu 3.- Press the Right Arrow button once to select Memory Reference then press OK 4.- The menu should now show - Print Memory List - Print Specified Document - Select Specified Document I am sure you can take it from there.