I have been running ArcGIS 10.5 on my PC (Windows 10 Home) since December with no issues. This past week I have started to get ActiveX Security Warnings when I click into a parameter field in any ArcToolbox tool.
Windows Security Warning
An ActiveX control on this page might be unsafe to interact with other parts of the page. Do you want to allow this interaction?
It doesn't seem to matter whether I click Yes or No, I can still modify the field and the tool still functions fine.
I am working through the answers to Why do ArcToolbox tools give ActiveX error?, although there doesn't appear to be an actual answer on that Q&A. Additionally it's back in the Windows XP/7 days with IE 7/8, and I'm running Win 10 with IE 11 (although that's never used). If it matters, the browsers we use are Firefox 53.0 (64-bit) and Chrome 58.0.3029.81 (64-bit).
The issue I am having sounds different as it's happening only when I click on the parameter field - not when I open the tool or, as I read elsewhere, ArcMap. The warning messages on that Q&A also have different text so it may be a completely different problem.
I have opened Internet Explorer (for the first time since getting this PC!) and looked at the Local Zone settings and everything for ActiveX is marked Enabled, including one about running without prompting:
I have also Disabled another one "Automatic Prompting for ActiveX Controls" but that didn't stop the message appearing.
I went through the suggested ActiveX settings from Problem: Issues with ActiveX controls when launching ArcMap, updated all my settings to match (the only one I had to change was the "Automatic Prompting for ActiveX Controls" one I changed in my testing above).
No new software has been installed on my PC in the past week.
What could have caused this to start appearing, and how do I fix it?