Unity-Technologies/UnityCsReference · error · BuildMethodException

Could not switch to build target '{0}', '{1}'.

Error message

Could not switch to build target '{0}', '{1}'.

What it means

Before building, the method calls EditorUserBuildSettings.SwitchActiveBuildTargetAsync(targetGroup, target) when the active target differs from the requested one. If the async switch fails, it throws BuildMethodException with the group and target display names, because proceeding to build against the wrong active target is invalid.

Source

Thrown at Editor/Mono/BuildPlayerWindowBuildMethods.cs:163

                }

                // See if we need to switch platforms and delay the build.  We do this whenever
                // we're trying to build for a target different from the active one so as to ensure
                // that the compiled script code we have loaded is built for the same platform we
                // are building for.  As we can't reload while our editor stuff is still executing,
                // we need to defer to after the next script reload then.
                bool delayToAfterScriptReload = false;
                if (EditorUserBuildSettings.activeBuildTarget != options.target ||
                    EditorUserBuildSettings.activeBuildTargetGroup != options.targetGroup)
                {
                    if (!EditorUserBuildSettings.SwitchActiveBuildTargetAsync(options.targetGroup, options.target))
                    {
                        // Switching the build target failed.  No point in trying to continue
                        // with a build.
                        var errStr = string.Format("Could not switch to build target '{0}', '{1}'.",
                            BuildPipeline.GetBuildTargetGroupDisplayName(options.targetGroup),
                            BuildPlatforms.instance.GetBuildTargetDisplayName(options.targetGroup, options.target, options.subtarget));
                        throw new BuildMethodException(errStr);
                    }

                    if (EditorApplication.isCompiling)
                        delayToAfterScriptReload = true;
                }

                bool locationPathExistedBeforeBuild = System.IO.Directory.Exists(options.locationPathName);
                // Trigger build.
                // Note: report will be null, if delayToAfterScriptReload = true
                var report = BuildPipeline.BuildPlayerFromUI(options, delayToAfterScriptReload);

                if (report != null
                )
                {
                    var resultStr = String.Format("Build completed with a result of '{0}' in {1} seconds ({2} ms) [{3} -> {4}, {5}]",
                        report.summary.result.ToString("g"),
                        Convert.ToInt32(report.summary.totalTime.TotalSeconds),
                        Convert.ToInt32(report.summary.totalTime.TotalMilliseconds),

View on GitHub (pinned to 225b0fbdb5)

Solutions

  1. Resolve any compiler errors in the project before switching/building for a different target.
  2. Install the target's support module so the switch can succeed.
  3. Set the active build target manually in Build Settings first to confirm the switch works, then run the scripted build.

Example fix

/* no source edit */
// before: scripted cross-platform build while project has compile errors -> switch fails
// after: fix compile errors, then re-run the build; or manually switch target in Build Settings first
Defensive patterns

Strategy: try-catch

Validate before calling

if (EditorUserBuildSettings.activeBuildTarget != options.target &&
    !EditorUserBuildSettings.SwitchActiveBuildTargetAsync(options.targetGroup, options.target))
    throw new InvalidOperationException("Target switch failed; resolve compile errors or install the module first.");

Try / catch

try { BuildPlayer(options); }
catch (BuildMethodException ex) when (ex.Message.Contains("Could not switch to build target"))
{ Debug.LogError("Fix compile errors / install module, then retry the cross-target build."); }

Prevention

When it happens

Trigger: The requested target/group differs from the active one and SwitchActiveBuildTargetAsync returns false (switch rejected, e.g. blocking compile error, platform module missing, or platform change unsupported).

Common situations: Scripted build for a different platform while the editor has compile errors blocking the target switch; switching to a target whose module isn't installed; switching targets while an async operation is in flight.

Related errors

AI-assisted analysis of Unity-Technologies/UnityCsReference@225b0fbdb5 (2026-08-13). Data as JSON: /api/errors/c1759959eba883b2. Report an issue: GitHub.