Hotfixes are small updates that are part of Windows Update. Some hotfixes are vital to security, others are updates to software and others bug fixes.
You may want to download them all, or you may only wish to install the ones you want. The problem with this is that they appear every time as an update, so you have to make sure you do not select it. This can be hard to remember seen as they are labeled as "KB" followed by a number. Using this number you can look up what is in the update on Microsoft's website.
Instead of having to remember all of the time, there is a much easier way to ensure it is not accidently installed through forgetting you did not want it. You can hide it.
To hide an update, simply go to Windows Update and check for updates. Any you do not wish to install, just right click it and select "Hide Update".