A checked build is an operating system and search-mode driver that has extra error checking and debugging information in the code to aid testing and debugging of the driver. Running with a checked build is slower and uses more memory. A checked build is done in a separate computer from the free build.
The purpose of the checked build of Microsoft Windows is to make identifying and diagnosing operating-system-level problems easier. The checked build differs from the standard build in the following ways:
- Many compiler optimizations (such as stack frame elimination) are disabled in the checked build. Disabling such optimizations makes it easier to understand disassembled machine instructions, and therefore it is easier to trace the cause of problems in system software.
- The checked build enables a large number of debugging checks in the operating system code and system-provided drivers. This helps the checked build identify internal inconsistencies and problems as soon as they occur.
Distribution media containing the checked build are clearly labeled "Debug/Checked Build." The checked build distribution medium contains the checked version of the operating system, plus checked versions of HALs, drivers, file systems, and even many user-mode components.
Because the checked build contains fewer optimizations and more debugging checks than the standard build, the checked build is both larger in size and slower to execute than the free build. As a result, the standard build is used in production environments unless it is necessary to use the checked build to identify serious problems.
A free build or retail build is the end user version of the operating system built with full optimization and all debugging information removed. A free build is faster and uses less memory. It also shows driver problems that a user might encounter such as error messages or a computer freeze.