COM Add-in did not load - fixed by installing in Program Files


Daniel, your software is amazing.
Unfortunately, after noticing on Windows 10 in the Office 365 version of Excel that the XL Toolbox tab was gone (it previously worked fine for months), I uninstalled then reinstalled.

The installation process went fine as admin.
But when I try to add the XL Toolbox from the Excel>DeveloperTab>Add-ins>COM Add-Ins, the check option showed that the tool was unloaded.


I had tried numerous times to check the box and press OK… nothing changed.
I also checked the registry, and everything seemed to be in its right place.

My only thought was that the Location: “file:///C:/Users/…” might be causing an issue. I only noticed because the other addins were all in the program files directories.

So, I unsinstalled. Then I reinstalled (XLToolbox-7.3.4.exe) as admin and used “C:\Program Files\XLToolbox” as the directory. Everything is now working as expected.
I began writing this post while it was not loaded, then solved the problem. So, this is a potential bug report, but I don’t really need followup.

Between the last time I used the XLToolbox and today, there was a server migration. So, maybe that had something to do with it. I have no idea.

Keep up the great work!


Thanks for this report! Over the past months, I have received a number of similar reports. While I personally have not experienced problems installing the Toolbox on Office 365/Windows 10, others users do. It’s unpredictable. Your solution might help others get it installed after all.

Microsoft have introduced a new “application programming interface” (API) for Office add-ins, which is based on JavaScript. While they still support the traditional .NET-based add-ins (with something called ‘Visual Studio Tools for Office’, VSTO), and even still support the ancient Visual Basic for Applications, I get the impression that JavaScript is the future of Office add-in development.

While I would love to explore moving the XL Toolbox to JavaScript, this would be yet another major rewrite of this add-in (which used to be a plain old Visual Basic for Applications add-in). At the same time, I have close to zero spare time to even maintain this add-in. So I’m glad when users find a way to make it work for themselves.

An additional issue is that I really should code-sign the add-in, i.e. use a cryptographic certificate to prove the authenticity of the add-in. Unfortunately, these certificates cost a lot of money and have to be renewed on an annual (or biennial, …) basis. If I were to do this, I’d have to change the business model and offer the add-in for money. I don’t really want to to that. However, code-signing would probably solve a lot of installation issues, because Microsoft get more and more picky (and rightly so) about installing pieces of software that are not signed with a certificate.