BCUninstaller/Bulk-Crap-Uninstaller · error · ArgumentException

Could not find Steam App with the ID {appIdStr}

Error message

Could not find Steam App with the ID {appIdStr}

What it means

An ArgumentException thrown by `SteamApplicationInfo.FromAppId` when no `appmanifest_<id>.acf` file matching the given AppID is found in any registered Steam library (SteamAppsLocations). The helper scans every library directory for a manifest whose numeric suffix equals the appId; if none matches, the app is considered not installed (or not installed via Steam) and the lookup fails.

Source

Thrown at source/SteamHelper/SteamApplicationInfo.cs:55

        {
            DirectoryInfo dir = null;
            FileInfo manifestFile = null;
            var appIdStr = appId.ToString("G");

            foreach (var steamAppsLocation in SteamInstallation.Instance.SteamAppsLocations)
            {
                var result = Directory.GetFiles(steamAppsLocation, @"appmanifest_*.acf")
                    .FirstOrDefault(x => appIdStr.Equals(Path.GetFileNameWithoutExtension(x).Substring(12), StringComparison.InvariantCulture));
                if (!string.IsNullOrEmpty(result))
                {
                    manifestFile = new FileInfo(result);
                    dir = new DirectoryInfo(steamAppsLocation);
                    break;
                }
            }

            if (dir == null)
                throw new ArgumentException("Could not find Steam App with the ID " + appIdStr);

            return FromParams(appId, manifestFile, dir);
        }

        private static SteamApplicationInfo FromParams(int appId, FileInfo manifestFile, DirectoryInfo containingAppsDir)
        {
            var appIdStr = appId.ToString("G");
            var output = new SteamApplicationInfo(appId);
            output.ManifestPath = manifestFile.FullName;

            //"C:\Steam\steam.exe" steam://uninstall/123
            output.UninstallString = $"\"{SteamInstallation.Instance.MainExecutableFilename}\" steam://uninstall/{appIdStr}";

            var manifestStrings = File.ReadAllLines(output.ManifestPath);
            output.Name = GetManifestValue(manifestStrings, "name");
            output.SizeOnDisk = GetManifestValue(manifestStrings, "SizeOnDisk");
            var installDirName = GetManifestValue(manifestStrings, "installdir");
            if (!string.IsNullOrEmpty(installDirName))

View on GitHub (pinned to 608321de98)

Solutions

1. Verify the app is currently installed by checking Steam's library UI.
2. Confirm the AppID is correct (look it up via `SteamHelper list`).
3. Ensure all Steam library folders are mounted and listed in `steamapps/libraryfolders.vdf`.
4. If the manifest was deleted but the app exists, reinstall via Steam then retry.

// Pre-check that a manifest exists for the id before calling FromAppId.
bool installed = SteamInstallation.Instance.SteamAppsLocations
    .Any(d => Directory.GetFiles(d, $"appmanifest_{appId}.acf").Length > 0);
if (!installed) return; // or report 'not installed'

try { var info = SteamApplicationInfo.FromAppId(appId); }
catch (ArgumentException ex) when (ex.Message.StartsWith("Could not find Steam App"))
{ /* treat as not-installed, skip or notify user */ }

When it happens

Trigger: Calling `FromAppId(<id>)` where the id does not correspond to an installed Steam app, the manifest file was deleted/moved, or the Steam library folder list is incomplete (libraryfolders.vdf not parsed).

Common situations: App was uninstalled manually by deleting files; Steam installed to a non-standard drive not registered in libraryfolders.vdf; the AppID came from an external source and was never installed; Steam library on a disconnected external drive.

Related errors

• Failed to detect your Steam installation. Launch Steam, exit
• Failed to get MainModule Directory
• File not found.
• Unknown range
• Not a Windows .exe file.

AI-assisted analysis of BCUninstaller/Bulk-Crap-Uninstaller@608321de98 (2026-08-13). Data as JSON: /api/errors/b2155956803cb2c7. Report an issue: GitHub.