OS Poisoning is a phenomenon that occurs when software is installed and uninstalled in an Operating System. When poisoning occurs, a computer system runs slower than normal. An OS can become so poisoned that the system ceases to function at all. Upgrading programs from an older version to a newer version can contribute a great deal to OS poisoning because of file version conflicts. Also, when poorly written programs are uninstalled, files that should have been removed are not. If you notice that your computer is not running as smoothly as it did when it was new, there is a possibilty that OS poisoning is responsible.

There is a great deal of debate over which Operating Systems suffers most from OS poisoning. Microsoft OSs become poisoned a great deal because of the Registry. The Registry is a huge file consisting of a tree-like structure that contains settings for almost all programs installed on the system. Each time a program is installed, it grows. Once it reaches a certain size, system performance becomes sluggish. In the Linux/Unix world, OS poisoning occurs mostly because of libraries and packages that are not exactly the right version for the programs that use them. While it is true that Windows suffers from versioning issues, Linux/Unix seems to have less backwards compatibility built into its shared libraries. The point is that no Operating System written yet is immune to OS poisoning.

The only way to prevent OS poisoning is to install only the programs that you need. The rate of poisoning can sometimes be minimized by uninstalling an old program before upgrading to a newer version. This, however, can cause you to lose settings, and is not always practical. The best defense is to pray that programmers improve their practices to help minimize the problem.