Cat On A Spreadsheet

Centralized Distribution of Your VBA Add-In

At this stage in the series, your Excel automation has undergone a significant transformation. Your macros are no longer scattered across workbooks - instead they live inside a structured .xlam add-in.Your source code is version controlled and your releases can be digitally signed and trusted.

What remains is the final step: making this add-in available to other users in a way that is controlled, predictable, and easy to maintain.

This is where most Excel solutions fail as distribution is often handled informally. Files are emailed, copied to desktops, or stored in multiple locations. Very quickly, different users are running different versions, bugs reappear, and support becomes reactive. A centralized distribution model solves this by ensuring that there is one authoritative version of the add-in, and that users always run it.

Moving from Local to Central Deployment

Until now, your add-in has lived on your local machine. To distribute it, you need a shared location that all users can access. In most environments, this will be a network drive or shared folder.

The key requirement is simple. The location must be:

accessible to all intended users
stable (the path should not change)
controlled (users should not modify the file)

A typical example might look like:

\\CompanyServer\ExcelAddins\AutomationTools.xlam

This file becomes the single source of truth for your deployed automation.

Ensuring Read-Only Access

One of the most important safeguards is preventing users from modifying the add-in. If users can edit the file, you immediately lose control over versioning and trust. The digital signature may be broken, and behaviour may diverge between users.

The solution is to set permissions so that:

users have read-only access
only you (or a controlled process) can update the file

This ensures that every user runs exactly the same code.

Installing the Add-In for Users

Each user needs to load the add-in into Excel. This only needs to be done once.

The user opens Excel and navigates to:

Developer → Excel Add-Ins → Browse

They then select the add-in from the shared location. Once added and enabled, Excel will load the add-in automatically on startup. From the user’s perspective, the macros now behave as if they are built into Excel itself.

What Happens When You Release a New Version

With centralized distribution, updating the add-in becomes straightforward. You produce a new version locally:

update your code
export modules to Git
rebuild the add-in
digitally sign it

Once ready, you replace the file in the shared location with the new version. The next time users open Excel, the updated add-in is loaded automatically. No emails. No manual updates. No confusion about versions.

This is the core advantage of centralized deployment.

Avoiding Locked File Issues

One practical issue appears quickly. If a user has Excel open while you try to replace the add-in file, the file may be locked - but there are several ways to handle this.

A simple approach is to communicate update windows and replace the file when users are not actively using Excel.

A more robust approach is to deploy versioned files and switch references, but for a single-developer setup, controlled timing is usually sufficient.

The important point is to be aware that Excel keeps the add-in file open while in use.

Adding a Version Check Inside the Add-In

At this stage, updates rely on users restarting Excel. In many cases, that is acceptable. However, you can make the system more transparent by embedding a version check.

Inside your add-in, store a version value.

  Public Function GetAddinVersion() As String
 
      GetAddinVersion = "1.0.0"
 
 End Function

You can then compare this to a version stored in a simple text file or worksheet in the shared location. If a newer version exists, you can notify the user.

  Public Sub CheckForUpdates()
 
      Dim currentVersion As String
 
      Dim latestVersion As String
 
      currentVersion = GetAddinVersion()
 
      latestVersion = GetLatestVersionFromServer()
 
      If currentVersion <> latestVersion Then
 
          MsgBox "A new version of the add-in is available. Please restart Excel.", vbInformation
 
      End If
 
 End Sub

This is not strictly required, but it improves visibility and user confidence.

Handling Breaking Changes

As your add-in evolves, some updates may change behaviour in ways that affect users’ workflows. Centralized distribution makes these changes immediate, which is powerful but also potentially disruptive. To manage this, changes should be deliberate. Version numbers should reflect the impact of changes. Communication should accompany significant updates. In some cases, temporary compatibility logic may be required.

This is where your earlier work on versioning and backward compatibility becomes important.

Rollback Strategy

No deployment strategy is complete without a rollback plan.

If a release introduces an issue, you should be able to restore the previous version quickly. The simplest approach is to keep a copy of the previous .xlam file.

If needed, replace the current file in the shared location with the previous version.

Because users load the add-in from that location, the rollback takes effect the next time Excel starts. This ability to recover quickly is one of the defining characteristics of a controlled system.

From Tool to Platform

At this point, something important has happened. Your automation is no longer a collection of macros.It is:

centrally managed
versioned
signed
distributed
controlled

Users interact with it as a stable component of their workflow rather than a file they need to manage. For a single developer, this is a powerful position. You can build, improve, and distribute automation with confidence, knowing that changes are consistent and reversible.

Where This Leaves You

By following this series, you have built a complete pipeline: You create functionality inside a structured add-in, you manage the source code in Git, you produce signed releases and you deploy them from a central location. This is, in essence, a lightweight software delivery system built entirely on top of Excel and VBA.

From here, you can go further. You can introduce automated builds, deeper logging, feature flags, or integration with enterprise identity and deployment systems. But even without those, what you now have is something most Excel environments never reach: a sustainable, professional, and scalable automation platform.