The _build checkout directory_ is the directory on agent where all of the project's sources reside. If you use [agent-side checkout mode|VCS Checkout Mode], build agent checks out the sources into this directory before the build. In case you use [server-side checkout mode|VCS Checkout Mode], TeamCity server sends to the agent incremental patches to update only the files changed since the last build in the given checkout directory.
The sources are placed into the checkout directory according to the mapping defined in the [VCS Checkout Rules].
You can specify the checkout directory when configuring *Checkout Settings* on the [Version Control Settings|Configuring VCS Roots] page, however, default (empty) value is recommended. See [#Custom checkout directory].
If not specified, automatically created directory is used with a generated name: {{<}}{{[Agent Work Directory]}}{{>/<VCS settings hash code>}}. The VCS settings hash code is calculated based on VCS roots and VCS settings used by the build configuration. Effectively, this means that the directory is shared between all the build configurations with the same VCS settings.
If you want to investigate some issue and need to know the directory used by a build configuration, you can get the directory from the build log, or you can refer to {{<}}{{[Agent Work Directory]}}{{>/directory.map}} generated file which lists build configurations with their last used directories.
In your [build script|Build Script Interaction with TeamCity] you may refer to the effective value of build checkout directory via the {{teamcity.build.checkoutDir}} [property|Configuring Build Parameters] provided by TeamCity.
h2. Custom checkout directory
In the most cases, leaving the checkout directory with default value (empty in UI) is recommended.
With this default checkout directory TeamCity ensures best performance and consistent incremental sources updates.
If for some reason you need to specify custom checkout directory (for example, the process of creating builds depends on some particular directory), please ensure that the following conditions are met:
- the checkout directory is not shared between build configurations with different VCS settings (otherwise TeamCity will perform [clean checkout|Clean Checkout] each time another build configuration is built int he directory);
- the content of the directory is not modified by other processes than a single TeamCity agent (otherwise TeamCity might be unable to ensure consistent incremental sources update). If this cannot be eliminated, make sure to turn on clean build checkout option for all the participating build configurations. This rule also applies to two TeamCity agents sharing the same working directory. As one TeamCity agent has no knowledge of another, another agent is appearing as an external process to it.
Please also note that content of the checkout directory can be deleted by TeamCity under [certain circumstances|Clean Checkout#Automatic Clean Checkout].
h2. Automatic Checkout Directory Cleaning
Checkout directories are automatically deleted from disk if not used (no builds were run on the agent using the directory as checkout directory) for a specified period of time (8 days by default).
({hidden-data}old section name for obsolete anchors:{hidden-data}{anchor:Cleaning Directory in Background}Please also see ensuring [free disk space case|Free disk space] when the checkout directory can be cleaned automatically.)
...