Table of Contents

Avoid Invalid Characters in Object Names

  • 2026-01-09
  • Morten Lønskov

Overview

This best practice rule identifies objects whose names contain invalid control characters (non-printable characters excluding standard whitespace). These characters can cause deployment failures, rendering issues, and data corruption.

  • Category: Error Prevention
  • Severity: High (3)

Applies To

  • Tables
  • Measures
  • Hierarchies
  • Levels
  • Perspectives
  • Partitions
  • Data Columns
  • Calculated Columns
  • Calculated Table Columns
  • KPIs
  • Model Roles
  • Calculation Groups
  • Calculation Items

Why This Matters

Control characters in object names cause serious issues:

  • Deployment failures: Power BI Service and Analysis Services may reject models with invalid characters
  • Rendering problems: Client tools may display garbled or invisible names
  • DAX parsing errors: Invalid characters can break DAX expressions referencing the object
  • XML corruption: Model metadata (TMSL/XMLA) may become malformed
  • Copy/paste issues: Names may not transfer correctly between applications
  • Encoding problems: Cross-platform compatibility issues

Standard whitespace (spaces, newlines, carriage returns) is allowed, but control characters should be removed.

When This Rule Triggers

The rule triggers when an object's name contains control characters that are not standard whitespace:

Name.ToCharArray().Any(char.IsControl(it) and !char.IsWhiteSpace(it))

This detects problematic characters while allowing legitimate whitespace formatting.

How to Fix

Automatic Fix

This rule includes an automatic fix that replaces invalid characters with spaces:

Name = string.Concat(
    it.Name.ToCharArray().Select(
        c => (char.IsControl(c) && !char.IsWhiteSpace(c)) ? ' ' : c
    )
)

To apply:

  1. In the Best Practice Analyzer select flagged objects
  2. Click Apply Fix

Manual Fix

  1. In TOM Explorer, select the object
  2. In Properties pane, locate the Name field
  3. Edit the name to remove invalid characters
  4. Save changes

Common Causes

Cause 1: Copy/Paste from Rich Text

Copying names from Word documents, web pages, or emails can introduce hidden formatting characters.

Cause 2: Automated Name Generation

Scripts generating names may include control characters from source systems.

Cause 3: Data Import from External Sources

Importing metadata that contains encoding artifacts or control codes.

Example

Before Fix

Measure Name: "Total\x00Sales"  (contains NULL character)

Deployment fails with "Invalid character in object name"

After Fix

Measure Name: "Total Sales"  (NULL replaced with space)

Deploys successfully and displays correctly in all tools.

Compatibility Level

This rule applies to models with compatibility level 1200 and higher.

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