I apologize for the delay in responding. This is a “VSTO”-Addin (Visual Studio for Office), which is why you can’t simply choose a .DLL or .XLAM file. There is a file
XLToolboxForExcel.vsto which, when double-clicked, should install the add-in into Excel.
I just now installed the Toolbox on a fairly new Windows 10 machine which I had recently set up, but had forgotten to install the Toolbox:
One big problem is that the add-in is not cryptographically signed. Code-signing certificates are expensive, and you don’t buy them once, you have to rent them. That’s why I don’t have a proper certificate for the Toolbox. This issue keeps popping up though. You might also try to install the Toolbox with any antivirus software temporarily turned off (although I would expect that you had been presented with some sort of warning if antivirus really was a problem).
Finally, you could send me the installation log file which resides in the
%TEMP% folder (press WIN+R and enter %TEMP%). Sort by descending modified date and locate a file called
Setup Log 2020-02-xx #001.txt (where
xx is the current date of course). You can send me this as a private message in this forum or by email to daniel at xltoolbox dot net.
I’m sorry I can’t be of much more help right now.