Quartus II does not launch automatically when I double-click a qpf file. Why?

The program field quartus.exe may not be specified in the properties of the ****.qpf file.
Please check with the following method, and specify if it is different.

1. Right click qpf file → Properties
2. Confirm quartus.exe in the program field (If different, set .exe below again)
* When using a 64-bit OS
<<install directory>>\quartus\bin64\quartus.exe
For 32bit OS
<<install directory>>\quartus\bin\quartus.exe