PRINTER REFUSING TO PRINT IN BLACK ONLY, REQUIRING COLOR CARTRIGE PURCHASE.

[NDSPRT]

My HP Officejet Pro 8600 Plus e-All-in-One Printer - n911g used to give me the option of printing in black and white only if one of the color cartridges was empty.  Now it gives message the empty color cartridge must be replaced before printing can be resumed.    The printer only said the magenta color needed to be replaced.  So I go to the store and purchase a magenta cartridge.  Then tried to print.  Now it says the blue cartridge is empty.  Why didn't it say that last night before I made a trip to the store?  How could it indicate the blue cartridge had ink, then no ink when no color printing was done in the interim?  Why is there no longer the option to print in black only even if a color cartridge is empty?  Please answer these questions.  

[Repairatrooper]

Yes that is a big pain. Not in defense of the machine, but likely the cyan cartridge was just over the replace warning and in startup used just enough ink to push it over the edge. Statistically, most users will exhaust cyan/magenta/yellow within a small window of pages. However due to issues in the past where low ink warnings occurred too soon and resulted in very negative feedback from users, low cartridge programming has likely shifted in the other direction, resulting in situations like yours. Best advice is that  you check the ink levels before ordering or going to the store to see how low they are. If under 10% you likely want to have a spare on hand.