You can try use MATLAB to explicitly load the Solver add-in when you open Excel. Here is the sample code for this:
% Start Excel application
excelApp = actxserver('Excel.Application');
excelApp.Visible = true;
% Open the workbook
filePath = fullfile(pwd, 'fileName.xlsx');
workbook = excelApp.Workbooks.Open(filePath);
% Access the Add-ins collection
addIns = excelApp.AddIns;
%Find and load the Solver add-in
for i = 1:addIns.Count
if strcmp(addIns.Item(i).Name, 'Solver Add-In')
if ~addIns.Item(i).Installed
addIns.Item(i).Installed = true;
end
break;
end
end
I hope this helps!