Build cannot be stopped (Hang during publishing output parameter step)

Problem

When a build with explicitly declared output parameters in a configuration fails or is canceled before the parameters are assigned, TeamCity hangs on the step "Publishing output parameters." These builds remain displayed as "running" in TeamCity, even though the agents are available, and other builds run normally. Moreover, restarting agents or the server does not clear these stuck builds.

Cause

The issue occurs because of an exception thrown during the build finalization stage when TeamCity attempts to manage many unresolved output parameters. Specifically, unresolved parameters can lead to an identity exceeding 60 characters for a build problem entry, resulting in an exception and causing the build to stay in the "Publishing output parameters" state.

Resolution

JetBrains has acknowledged this as a product issue (registered as TW-99407) and plans to release a fix in TeamCity updates 2026.1 or 2025.11.4. In the meantime, consider the following workarounds:

1. Reduce the number of declared output parameters or define default values for them in the build configuration.
2. As an alternative, use input parameters instead of output parameters to mitigate the issue.
3. Attempt to restart the server or agents to clear the internal state of TeamCity manually.
4. Test early-access preview builds where the issue has been addressed, such as TeamCity 2025.11.4 EAP.

Note: After applying the fix or using the EAP build, any previously stuck builds may require time to resolve automatically during background processes, as experienced in this case. If the issue remains, contact JetBrains support for additional assistance.