Install

Install ModelxcelPro on Excel for Windows.

Five minutes from download to first signed cell. The installer ships in your invite email when commerce launches; this page is the reference for system requirements and troubleshooting.

Windows · Excel 2013 or laterMac not supported

System requirements

What you need.

Operating system

Windows 10 / 11 (64-bit)

Windows Server 2019+ also supported. Mac OS is not supported — see the FAQ below.

Microsoft Excel

2016 / 2019 / 2021 / Microsoft 365 (current)

Both perpetual and Microsoft 365 (subscription) editions of Excel are supported. 32-bit and 64-bit Excel both work.

.NET runtime

.NET Framework 4.8.1

Pre-installed on Windows 10 (since 19H1) and Windows 11. The installer detects and prompts if missing.

Disk & memory

~120 MB disk · 4 GB+ RAM recommended

Memory headroom matters most for Worksheet Map and Risk Heatmap on workbooks above 200k cells.

Install steps

Five minutes from zero.

  1. 01

    Download the installer

    Your invite email includes a signed installer link when commerce launches. The installer ships as a .exe with an embedded VSTO manifest. (Public installer link arrives with M3 commerce launch.)

  2. 02

    Close Excel

    The installer registers a new VSTO manifest with Excel. If Excel is open, you'll be prompted to close it.

  3. 03

    Run the installer

    The installer is signed by ModelXcel; you'll see the publisher name in the Windows User Account Control prompt. Default install path: %LocalAppData%\ModelxcelPro. No admin rights required for per-user installs.

  4. 04

    Open Excel and activate

    A new ModelXcel Pro tab appears in the ribbon with eight groups: Format, Formula Tools, Name Conversion, Map, Compare, Audit, Proof, and Help. Click License Status in the Help group and paste your .lic file from your invite email.

  5. 05

    Try it on a real cell

    Press Ctrl+Shift+I on any formula to open TrustLens, or open the Help pane from the ribbon's Help group. The Getting Started guide walks through Smart Format, Proof, and Compare.

For IT teams

License file format.

Each .lic file is a signed JSON envelope that your add-in validates offline against a baked-in ECDSA P-256 key set. No phone-home is required for activation.

modelxcelpro.lic (excerpt)
{
  "format": "ModelxcelPro.LicenseEnvelope",
  "schemaVersion": 3,
  "payload": "eyJmb3JtYXQiOiJNb2RlbHhjZWxQcm8uTGljZW5zZVBheWxvYWQi...",
  "signature": {
    "alg": "ES256",
    "kid": "key-2026-01",
    "value": "..."
  }
}

The payload is base64url JSON carrying licenseId, email, issue and expiry dates, machine code, and feature scope. Validation is fully offline — the add-in never phones home. Revocation of a compromised signing key ships as key-status metadata in add-in updates.

Troubleshooting

Common install issues.

  • The ModelXcel Pro tab doesn't appear in the ribbon

    Open File → Options → Add-ins. At the bottom, change "Manage" to COM Add-ins and click Go. Tick "ModelxcelPro" and click OK. If ModelxcelPro is missing from the list, the install didn't complete; re-run the installer with Excel closed.

  • "Cannot load this add-in" error on Excel startup

    Usually means your .NET Framework is below 4.8.1. Run Windows Update or download .NET Framework 4.8.1 from Microsoft directly. Restart Excel after install.

  • License file rejected

    Re-download from your invite email when commerce launches; license files are tied to the email address that requested them. If still rejected, add your machine code on /account/machines, then use /account/licenses to download a fresh .lic file.

  • Conflicts with other add-ins

    ModelxcelPro doesn't hijack global Excel shortcuts. Both can be installed simultaneously. If a keyboard shortcut overlaps with another add-in, you can rebind ModelxcelPro shortcuts from Format → Settings → Keyboard.

  • Excel for Mac

    ModelxcelPro is built on .NET Framework 4.8.1 (VSTO) which Excel for Mac doesn't support. We don't plan to port until a clean cross-platform path exists. If Mac support is critical, talk to us about Enterprise — we may have an alternative for specific workflows.

  • Where are my diagnostic logs?

    ModelxcelPro writes a daily-rotated log to %LOCALAPPDATA%\ModelxcelPro\Logs\modelxcelpro-YYYYMMDD.log. Crashes go to %LOCALAPPDATA%\ModelxcelPro\crash.log (append-only). When opening a support ticket at support@modelxcel.com, attach the most recent daily log file — it dramatically speeds up diagnosis. Logs contain command names, durations, and error messages only; they never contain formula contents, cell values, file names, or workbook content.