The issue can be replicated by right clicking on any word document and trying to click the PDF maker options. You get an error that says:
The Security level is set to High.
Please run the application which created this document, in the "Security Warning" dialog select the checkbox "Always trust macros from this source" and enable macro's created by Adobe Systems Inc.
When you open the document, there is no option for Security warning and trusting macro's as the document is already a trusted document. Adobe is also listed as a trusted publisher in the macro settings.
We have 2 computers with this issue.
Sorry for the delay in response.
As you have mentioned above, when you right click on PDF to use the PDF maker the error message appears.
Did you try to combine the files directly from the Adobe Acrobat application?
If not, please try and check if you get the same error message.
When you open the same file on which you get the error message, go to File menu and check if you get any security warning area or enable content option available there.
Is it an issue with all the files or with some particular files?
Please make sure that the application is updated to the latest patch released.
If you are experiencing the issue with the same files on both the systems, it can be the issue with the files.
Is it possible to share the file with us? If yes, please refer the steps provided here How to share a file using Adobe Document Cloud
Let us know if you have any questions or need any help.
This issue was caused by Word being forced to run as Admin by one of our document management systems. Once Word was set to not run as admin this issue was resolved.