MS Word security notice when creating a Word object and Word is already running

[nealb]

I have a VB6 app that creates a Word object. (Windows 11 PC)

DIM MSWord as object
Set MSWord = CreateObject("word.application","localhost")

The app calls macros that exist in Word template Normal.dotm.

For years this app has worked flawlessly until this week where I now get a "Microsoft Word Security Notice". The security notice message box gives the following message:

"Microsoft Office has identified a potential security concern."
"Microsoft has blocked macros from running because the source of the file is untrusted."
"File Path: C:\Users\signu\AppData\Local\Microsoft\Windows\INetCache\Content.Word\~WRC0004.tmp"

I have discovered that this security notice only appears if a desktop instance of Word is already running. If Word isn't already running then my app works.

If the security notice window isn't closed with about 10 seconds, VB errors out with a the following error:

Error -2146959355
Server execution failed

I have also discovered that if Word is already running but Normal.dotm has no macros in it, then the security notice doesn't appear when I run my app. But of course my app can't work correctly without the macros.

I have the path to Normal.dotm set as a trusted location in Word's trust centre options.

Has anyone else suddenly got this Word security notice? Any ideas?