Only the Repair and Remove options are available in the msi
I have checked this issue by installing previous versions Aspose.Email for .NET 17.3 msi, 17.4 and 17.5 in a sequence. I am afraid that no issue is observed and 17.5 version was installed without any error when 17.4 was installed already.
However, if we try to install ver 17.5 again, after installing it, there are two options only i.e. Repair and Remove. It seems that ver 17.5 is already installed on your system. You may please remove it and install it again and share the feedback.
I am not sure what happened. When I clicked the download link earlier today I got "aspose.email_product_family.zip" which had 17.4. I just tried it again and now I get "aspose.email_17.5.0.msi". Running this msi worked fine and 17.5 is now installed.
Thanks for the update!
You are welcome.