I started experiencing very slow initial load time for Opera, and checked Windows Error logs for detail. Here's what I found in the Microsoft Windows Diagnostic Performance/Operational log:
This application took longer than usual to start up, resulting in a performance degradation in the system startup process:
File Name : opera.exe
Friendly Name : Opera Internet Browser
Version : 41.0.2353.69
Total Time : 9977ms
Degradation Time : 4977ms
Incident Time (UTC): 2016-12-24T15:18:32.671600300Z
More detail:
EventID: 101
OpCode: Boot Degradation
Screenshots available.