Login fails with error message with HRESULT: 0x80131515

Symptom

When starting CDCplus.exe, the system shows the error message:

Could not load file or assembly '<filename>' or one of its dependencies. Operation is not supported.
(Exception from HRESULT: 0x80131515)"

Background

Windows mistrusts some libraries that are copied from external sources into system directories like c:\Program Files, marks them as insecure and blocks execution. This can happen on some systems, depending on the individual security policy situation. The block can be removed manually.

Solution

• Navigate to the progam directory of CDCplus.exe and find the DLL named in the error message.
• Right-click the DLL and select "Properties".
• On the tab "General" under "Security", there is the entry:

  The file came from another computer and might be blocked to help protect this computer.

• Click the button "Unblock".