One of the customer reported an AutoCAD error message „copy to clipboard failed“ when using CTRL+C to copy features through all versions (2012 to 2016) and verticals (ACA, Map)
The issue was that a few users in a pilot group got Avecto Defendpoint client installed to monitor their daily tasks in order to personalize windows user rights.
As soon as Avecto Defendpoint client was installed AutoCAD threw the error message for CTRL+C.
The context menu function „copy selection“ worked as expected and could be used as workaround.
Using CTRL+C in other applications, e.g. MS Office (Word, Excel, Outlook) is working fine without issues.
Here is the fix for this issue.
https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/sfdcarticles/sfdcarticles/Avecto-Defendpoint-conflicts-with-AutoCAD.html