A build can be pinned to prevent it from being removed when a clean-up procedure is executed, as stipulated by the clean-up policy.
To pin/unpin a build:
on the Build Results page, select Pin in the Actions drop-down menu
on the Overview tab of the Build Configuration Home page, select the Pin build action
The Pin/Unpin build dialog also allows you to tag the build.
If the build has snapshot dependencies, the "Apply to all snapshot dependencies" box appears. Check this box to apply the actions (pinning/unpinning, adding / removing tags) to all dependency builds of the current build.
Concepts: Clean-up policy