duplicati/duplicati · error · UserInformationException

CannotCreateRandomName

CannotCreateRandomName

Error message

Unable to find a unique name for the database, please use --dbpath

What it means

Thrown by CLIDatabaseLocator when auto-creating a new database file: it tries up to 100 randomly generated names and if every candidate path already exists on disk, it gives up and asks the user to supply --dbpath. This is a guard against pathological folder state, not normal operation.

Source

Thrown at Duplicati/Library/Main/CLIDatabaseLocator.cs:219

            if (matches.Count == 0)
            {
                var backupname = options.BackupName;
                if (string.IsNullOrEmpty(backupname) || backupname == Options.DefaultBackupName)
                    backupname = GenerateRandomName();
                else
                {
                    foreach (var c in System.IO.Path.GetInvalidFileNameChars())
                        backupname = backupname.Replace(c.ToString(), "");
                }

                var newpath = System.IO.Path.Combine(folder, backupname + ".sqlite");
                int max_tries = 100;
                while (System.IO.File.Exists(newpath) && max_tries-- > 0)
                    newpath = System.IO.Path.Combine(folder, GenerateRandomName());

                if (System.IO.File.Exists(newpath))
                    throw new Duplicati.Library.Interface.UserInformationException("Unable to find a unique name for the database, please use --dbpath", "CannotCreateRandomName");

                //Create a new one, add it to the list, and save it
                configs.Add(new BackendEntry()
                {
                    Type = type,
                    Server = server,
                    Path = path,
                    Prefix = prefix,
                    Username = username,
                    //Passwordhash = password,
                    Port = port,
                    Databasepath = newpath,
                    ParameterFile = null,
                    IsSyncDb = isSyncDb
                });

                var settings = new Newtonsoft.Json.JsonSerializerSettings();
                settings.Formatting = Newtonsoft.Json.Formatting.Indented;

View on GitHub (pinned to 3f348be3e3)

Solutions

1. Supply --dbpath to specify an exact, unused database file path.
2. Clean up the target folder: remove orphaned randomly-named .sqlite files.
3. Verify write access and free space on the folder.

Example fix

// before: locator cannot find a free random name
duplicati backup "s3://host/path"

// after: explicit database path
duplicati backup "s3://host/path" --dbpath=/data/duplicati/new.sqlite

// Avoid relying on random-name collision avoidance
if (string.IsNullOrEmpty(dbPath))
    throw new ArgumentException("Supply --dbpath to guarantee a unique database file");
if (System.IO.File.Exists(dbPath)) throw new InvalidOperationException($"{dbPath} already exists");

try { var path = CLIDatabaseLocator.GetDatabasePath(...); }
catch (UserInformationException ex) when (ex.HelpID == "CannotCreateRandomName")
{ /* fall back to an explicit --dbpath chosen by the caller */ }

When it happens

Trigger: autoCreate is true, no existing match is found, and System.IO.File.Exists returns true for all 100 random names generated under the configured folder.

Common situations: The database folder has accumulated hundreds of randomly-named .sqlite files (e.g. from many abandoned backups or a bug leaking files); filesystem/permission issues make File.Exists behave unexpectedly; a very small name space collision (GenerateRandomName collision).

Related errors

• MultipleLocalDatabaseSourcesFound
• Usage: dotnet run <path-to-source-folder> ["copyright name"]
• Start path not found: {startpath}
• KeepWebservicePasswordWithPassword
• InvalidAgentSettingsKey

AI-assisted analysis of duplicati/duplicati@3f348be3e3 (2026-08-13). Data as JSON: /api/errors/06defcda5dbe564f. Report an issue: GitHub.