While using automatic update tool, you may get 0xf0804 CBS_E_OPEN_FAILED Error in Windows. This is one of the most critical error issues that can badly abrupt the entire functioning of the computer. You cannot be able to access any application without fixing Windows error code 0xf0804. Reasons are very common but create unexpected issue. Virus infections, registry problem, etc are some of the main reasons behind the error. You should go through the manual methods if you are technically qualified or you can also use third party Advanced System Repair tool to fix the issue automatically.