microsoft/aspire · error · DistributedApplicationException

Application orchestrator dependency check returned an error

Error message

Application orchestrator dependency check returned an error: {ex.Message} {stderr}{newline}{stdout}

What it means

Any unexpected exception thrown while launching or reading output from the dcp dependency check is caught and rethrown as a DistributedApplicationException containing the exception message plus dcp's stderr/stdout. It preserves process output for diagnosis while normalizing the failure type.

Solutions

Inspect the wrapped ex.Message and captured stderr/stdout to find the root cause.
Re-run the AppHost — many launch failures are transient.
Reinstall/repair the dcp binary if the message indicates a crash or bad executable format.
Check for external interference (antivirus quarantine, security policy blocking process launch).

Defensive patterns

Strategy: retry

Try / catch

try
{
    var info = await dcpDependencyCheck.GetDcpInfoAsync(ct);
}
catch (DistributedApplicationException ex)
{
    // transient launch/IO failures are worth one retry; check embedded stderr for root cause
    await Task.Delay(TimeSpan.FromSeconds(2), ct);
    var info = await dcpDependencyCheck.GetDcpInfoAsync(ct);
}

Prevention

Exclude the Aspire/dcp directories from antivirus real-time scanning.
Run AppHosts in environments that permit spawning child processes.
Keep the machine's process limits (ulimit, job objects) within normal bounds.
Treat one retry before surfacing the failure to the user.

When it happens

Trigger: Inside GetDcpInfoAsync's catch filter: any exception other than DistributedApplicationException, and OperationCanceledException only when the caller did not request cancellation (e.g. dcp process failed to start, streams faulted, timeout via WaitAsync).

Common situations: dcp binary killed by antivirus or signal, pipe/stream errors while capturing output, transient OS-level process launch failures, or a hung dcp invocation cancelled by an internal timeout.

Related errors

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/521b7c4967ad6963. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting/Dcp/DcpDependencyCheck.cs:116

                {
                    return null; // Best effort
                }

                var dcpInfo = JsonSerializer.Deserialize<DcpInfo>(output);
                if (dcpInfo == null)
                {
                    return null; // Best effort
                }

                EnsureDcpVersion(dcpInfo);
                _dcpInfo = dcpInfo;
                return dcpInfo;
            }
            catch (Exception ex) when
                (ex is not DistributedApplicationException
                && !(ex is OperationCanceledException && cancellationToken.IsCancellationRequested))
            {
                throw new DistributedApplicationException(string.Format(
                    CultureInfo.InvariantCulture,
                    MessageStrings.DcpDependencyCheckFailedMessage,
                    $"{ex.Message} {errorStringBuilder.ToString()}{Environment.NewLine}{outputStringBuilder.ToString()}"
                ));
            }
            finally
            {
                if (processDisposable != null)
                {
                    try
                    {
                        await processDisposable.DisposeAsync().ConfigureAwait(false);
                    }
                    catch { } // Dispose (dcp info process termination) is best effort.
                }
            }
        }
        finally

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