It was McAffee...
Because I installed TV9 successfully a couple times, my annoyance with this issue led me to find this event message in the Application log which I overlooked...
Event Type: Information
Event Source: McLogEvent
Event Category: None
Event ID: 257
Date: 7/15/2014
Time: 7:41:28 AM
User: NT AUTHORITY\SYSTEM
Computer: mycomputer
Description:
Would be blocked by access protection rule (rule is in warn-only mode) (Common Standard Protection:Prevent common programs from running files from the Temp folder).
So it was McAffee that was blocking something in the C:\TEMP, even though:
- my system TEMP and TMP environment variables are both set to C:\Windows\Temp, and
- my user's TEMP and TMP are set to a TEMP folder in my user profile.
The following Archived discussion relates ...
https://community.mcafee.com/thread/38446