You didn’t provide much information about your system such as operating system, mail client etc. I would guess that you have a corrupted registry entry. Task ‘machine.domain.xom – Sending and Receiving’ reported error (0x800CCC0B) :’Unknown Error 0x800CCC0B’ Or Task Sending and Receiving’ reported error (0x800CCC0B):’Unknown Error 0x800CCC0B’ To resolve the issue, you will need to fix the corrupt registry problem.The registry is where all your information is stored about what and how programs should run on your computer. You may have to repair or reinstall your mail program. Or if it’s XP perhaps do a repair install to fix the problem.