iOfficeAI/OfficeCLI · error · ArgumentException

Invalid sheet name 'History': reserved by Excel for the chan

Error message

Invalid sheet name 'History': reserved by Excel for the change-history sheet.

What it means

The name 'History' (case-insensitive) is reserved by Excel for the workbook's built-in change-history (Track Changes) sheet. Creating a user sheet with that name corrupts the change-tracking feature, so the library rejects it as the final guard in ValidateSheetName.

Source

Thrown at src/officecli/Handlers/Excel/ExcelHandler.Helpers.Validation.cs:335

    }

    internal static void ValidateSheetName(string name)
    {
        if (string.IsNullOrWhiteSpace(name))
            throw new ArgumentException("Invalid sheet name: name cannot be empty or whitespace.");
        if (name.Length > 31)
            throw new ArgumentException(
                $"Invalid sheet name '{name}': length {name.Length} exceeds Excel's 31-char limit.");
        var forbidden = new[] { '\\', '/', '?', '*', ':', '[', ']' };
        var hit = name.IndexOfAny(forbidden);
        if (hit >= 0)
            throw new ArgumentException(
                $"Invalid sheet name '{name}': contains forbidden character '{name[hit]}'. Excel rejects any of: \\ / ? * : [ ]");
        if (name.StartsWith('\'') || name.EndsWith('\''))
            throw new ArgumentException(
                $"Invalid sheet name '{name}': cannot start or end with an apostrophe (').");
        if (name.Equals("History", StringComparison.OrdinalIgnoreCase))
            throw new ArgumentException(
                "Invalid sheet name 'History': reserved by Excel for the change-history sheet.");
    }

    /// <summary>
    /// R35-3: cross-workbook cell formulas like "=[Other.xlsx]Sheet1!A1" or
    /// "=[1]Sheet1!A1" need an externalLinks part to resolve. Without one,
    /// Excel opens the file but the formula shows #REF!. Reject up-front
    /// rather than silently persist a broken formula.
    /// CONSISTENCY(cross-workbook-ref): mirrors the namedrange refersTo
    /// guard in ExcelHandler.Add.Tables.cs (R27-1).
    /// </summary>
    internal static void RejectCrossWorkbookFormula(string formula)
    {
        if (string.IsNullOrEmpty(formula)) return;
        var trimmed = formula.TrimStart('=', ' ', '\t');
        // CONSISTENCY(cross-workbook-vs-structured-ref): the older `^\[` guard
        // also matched OOXML structured table references like `[@Price]` and
        // `[Price]*[Qty]`, falsely rejecting valid Excel-365 formulas. Real

View on GitHub (pinned to 1ced45e900)

Solutions

1. Rename to a non-reserved alternative: 'ChangeLog', 'AuditTrail', 'EditHistory'.
2. Maintain a reserved-names list and disambiguate at the input boundary.

Example fix

// before
wb.AddSheet("History");

// after
wb.AddSheet("ChangeLog");

static string AvoidReservedSheetName(string n) =>
    n.Equals("History", StringComparison.OrdinalIgnoreCase) ? n + "_" : n;

try { wb.AddSheet(name); }
catch (ArgumentException ex) when (ex.Message.Contains("reserved")) {
    wb.AddSheet(name + "_");
}

When it happens

Trigger: AddSheet or rename to any casing of 'History' — HISTORY, history, HiStOrY all trip the OrdinalIgnoreCase equality check.

Common situations: Generic 'History' label for an audit log or changelog tab; localized or styled variants; auto-generated names that happen to collide.

Related errors

• Property 'sqref' (or 'range'/'ref') is required for validati
• Invalid sheet name: name cannot be empty or whitespace.
• Invalid sheet name '{name}': length {name.Length} exceeds Ex
• Invalid sheet name '{name}': contains forbidden character '{
• Invalid sheet name '{name}': cannot start or end with an apo

AI-assisted analysis of iOfficeAI/OfficeCLI@1ced45e900 (2026-08-13). Data as JSON: /api/errors/9550444216b9707a. Report an issue: GitHub.