What are hotfixes, and when should I install them?
Hotfixes are usually bug-fixes that address a specific issue discovered after the release of the last major service pack. Service Packs roll up a number of individual packages into a single update which is usually more convenient for the end user to install – they are published relatively infrequently. A service pack will include all hotfixes released up to that point. If you are affected by a specifc issue for which a hotfix has been released, then you might like to download and apply the hotfix for that issue. Generally, however, unless you are affected by that specific issue, or the hotfix involves a critical issue for all users, you are advised to wait for the next Service Pack as additional testing will have taken place on the updated component to ensure its wider stability.
