Display fax gives a warning "received in memory" we also have a warning "prepare black toner" We can not print the fax! What can we do?

This fax machine stores the faxes in memory and then prints them out.

If it's unable to print them, is either because there is no paper or no ink.
The memory eventually gets full and stops receiving faxes.

you have received faxes, but they can't be print until you replace toner because probably you have TONER EMPTY message also on the display.
You can buy only fuse for toner cartridge (25mm, 250V/ 0,063A or 0,1A and maximum 0,125A)
When you pull out toner cartridge you will see the glass fuse on the front left side of the cartridge.
The new fuse will reset toner empty condition
pifonski

your toner is empty refill or replace it. You can continue printing when the toner is empty but the faxes recieved will not be printed till the toner empty light is reset.

It will depend on the model and make and you have not supplied that information.
If this information in memory was received information then the machine should print out the documents as long as there is nothing in the display saying it needs toner, paper etc, etc.
If it is not received information in memory then it can only be scanned information for copying or transmitting....again, not knowing make or model...you should be able to use your users manual and delete the pages you have stored into memory.

Please change the toner and feed the papers. It will print all the faxes recd in memory.

I just checked this out as I had the same problem. It seems that the machine is programmed to stop printing faxes when the Toner is "out". Even though the toner is not completely out. I was positive that the note on the screen was false since I could print out documents and copies (I am not using Samsung original Toner). But the fax will refuse to print.  I fixed this by changing the toner (again with a non-Samsung toner) and it is printing all the faxes in memory.  It is stupid that they haven't set up a menu item to force it to print all the faxes in memory but voila, that seems to be the fix. I guess this is a way for them to control that we only use Samsung toner. 

Dear guys, your toner cartridge is low and as a preventive measure, the unit stores the faxes in order to give priority to copying and printing. If you are using remanufactured cartridges, the unit might not be displaying the low toner warning.

press menu#1934menu.it comes to tech. mode press the right arrow beside the enter key 3 times .it comes to cartridge mode press enter and wait it works.

In 3 second make combination on you Samsung 4521F 'Menu'-#-1-9-3-4. You will enter in tech menu. Select 'toner'-new toner-yes. You will receive faxes. It really works.

TYPICALLY A FAX MACHINE WILL RECEIVE MESSAGE IN MEMORY WHEN NO PAPER OR TONER/INK FINISHED INDICATION IS THERE, REPLENISH THESE SUPPLIES WITH GENUINE ONES AND FAX WILL START PRINTING. IF PROBLEM IS NOT SOLVED , PLEASE TRY TO CLEAR THE SETTING FOR MEMORY RECEIVING, IF STILL NOT SOLVED TRY BRINGING THE MACHINBE TO FACTROY SET SETTING BY CLEARING THE MEMORY. HAPPY FAXING OMNIPRESENT