Depending on where the compass is located on the surface of the Earth the angle between true north and magnetic north, called magnetic declination can vary widely with geographic location. The local magnetic declination is given on most maps, to allow the map to be oriented with a compass parallel to true north.
2] KB2939087 recommends in case you are unable to install the Windows 8.1 Update package KB2919355 via Windows Update, then you should download and install the package manually. 3] If you receive Error 0x80071a91 when installing KB2919355 on Windows 8.1, Microsoft has released a patch to fix this issue.t should therefore first be installed on your system before your attempt to install Windows 8.1 Update or KB2919355. Go get it here if your computer does not have it. 1] If your Windows 8.1 Update has failed to installed, you need to clean up the corrupted installation.
Our install scenario requires a certain KB(Windows Update) to be installed. The problem is, there are packages that supersede that specific update, making the registry search for that specific KB useless. For example, I need to determine if the computer has KB-X. KB-X is superseded by KB-Y. In effect, there could be a computer that only has KB-Y because it doesn't need those it superseded.