BCUninstaller/Bulk-Crap-Uninstaller · error · IOException

regedit.exe returned error code

Error message

regedit.exe returned error code: {pr.ExitCode}

What it means

Thrown by RunRegeditCommand when regedit.exe exits with a non-zero exit code within the timeout. The message embeds the actual code (e.g. 'regedit.exe returned error code: 1'). regedit is invoked with /e to export, so a non-zero exit typically means the target key does not exist, the path syntax was rejected, or access was denied.

Solutions

1. Verify the key exists immediately before export (the helper already does an OpenRegistryKey check; ensure your path matches).
2. Run the process elevated so regedit can read the target hive.
3. Sanitize the path for quotes/backslashes and confirm the temp directory is writable.
4. Capture pr.ExitCode in your own log to map the code to a cause (regedit uses generic non-zero for most failures).

Example fix

// before
var lines = ExportRegistryHelper(userPath); // userPath may not exist

// after
if (RegistryTools.OpenRegistryKey(userPath) != null)
    var lines = ExportRegistryHelper(userPath);

if (RegistryTools.OpenRegistryKey(registryPath) == null)
    return null; // key missing; regedit would exit non-zero

try { var lines = ExportRegistryHelper(path); }
catch (IOException ex) when (ex.Message.Contains("error code"))
{ var code = ex.Message; /* parse code, log, surface actionable message */ }

When it happens

Trigger: Exporting a registry path that does not exist; passing a malformed path to regedit; running without privileges to read the requested hive; tempFile path containing characters regedit rejects.

Common situations: Keys deleted between the existence pre-check and the export; paths with embedded quotes that break the /e argument quoting; non-admin process exporting from HKLM; locale-specific path separators.

Related errors

• Could not close running instance of Regedit
• Failed to open regedit.exe
• regedit.exe failed to execute properly
• Failed to set the last user registry key
• Cannot remove the default value

AI-assisted analysis of BCUninstaller/Bulk-Crap-Uninstaller@608321de98 (2026-08-13). Data as JSON: /api/errors/3257c8f5bd657e28. Report an issue: GitHub.

Appendix: source

Thrown at source/KlocTools/Tools/RegistryTools.cs:406

        {
            foreach (var process in Process.GetProcessesByName("regedit"))
            {
                try { process.Kill(); }
                catch (InvalidOperationException) { }
                catch (Win32Exception) { }
            }

            var startInfo = new ProcessStartInfo("regedit.exe", command)
            { UseShellExecute = false };
            var pr = startInfo.Start();

            if (!pr.WaitForExit(50000))
            {
                pr.Kill();
                throw new IOException("regedit.exe failed to execute properly");
            }
            if (pr.ExitCode != 0)
                throw new IOException("regedit.exe returned error code: " + pr.ExitCode);
        }

        private static string[] ExportRegistryHelper(string registryPath)
        {
            // Check if the key exists
            try
            {
                OpenRegistryKey(registryPath).Close();
            }
            catch
            {
                return null;
            }

            var temp = Path.GetTempPath();
            var tempDirectory = Directory.CreateDirectory(Path.Combine(temp, "BCU"));
            var tempFile = Path.Combine(tempDirectory.FullName, "tempBackup.reg");

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