Hi Friend, I am Sofia Carter. Among the various HP printer errors, the hp printer won't print in color is the one commonly encountered by the users while trying to print the documents. The good news is, you can easily fix the problem. The HP printer will not print black if something is wrong with the print cartridge. So, you need to take out the black HP print cartridge and make sure that it has enough ink to print the document. If necessary, replace the ink cartridge with the new one. Also, make sure it is properly placed and installed in the appropriate slot. If the vent of the cartridge is clogged, you need to clean it to fix the issue.