In my tests with Windows 10 64-bit I found out that I would prefer to continue to run my (quite old) MS Word (= winword.exe) in the 32-bit mode. (If you want to know why: I have explained it at the end of this post.*) I am aware that there are two basic possibilities: - To use a virtual machine - to establish a dual boot of the 32-bit and 64-bit build of Windows. But both methods are by far too heavy and complicated for my aim. Via Google I found out that perhaps there could be a third way: the use of CorFlags.exe (A good description of CorFlags.exe can be found e.g. here: https://gaebster.ch/run-64-bit-as-32-bit/ [see the last chapter "How to run 32 bit Application on a 64 bit OS"].) So I would be interested if someone has experience with CorFlags.exe (or can otherwise tell me if I should give it a try). -------------------- *[That's the issue for which I would need a solution: My old version of MS Word runs fine under Windows 64-bit. But I got accustomed to using it together with an (also quite old) add-in that offers a much more comfortable possibility to search within documents than Word itself does. And this add-in unfortunately does not start any longer with Windows 64-bit. And I think that I found the explanation in this excellent article: https://www.techsupportalert.com/content/how-windows7-vista64-support-32bit-applications.htm They write there: This seems to be the reason why the search add-in does not start any longer. So by using MS Word as a 32-bit application I hope that I could solve the problem.]