ExifTool reverts back from 9.79 to 9.78 automatically

[MOL]

EDIT:
Found it.  My system is set up with an SSD for the operating system and program files, and a hard drive for data.  Somehow my application folder (including the old exiftool.exe) got copied from the HD into the SSD's 'Program Files(x86)' system folder and the desktop shortcut was automatically changed by the OS to point to this file location.  So every time I ran the program from the hard drive it extracted the old ExifTool version again.  Strange, because  I never use the SSD for software testing.

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Hi Phil

I'm experiencing a strange behavior here since I updated to 9.79 .  When I install a new version, I usually delete the files in the Temp folder (see below), copy the new Windows *.exe to the folder where my application resides, rename it to exiftool.exe, and all is good.  Not this time though.  When I start my application from within Windows Explorer, everything works as expected, but when I start the program the usual way via a click on a desktop icon, ExifTool automatically reverts back to version 9.78 .  I have no idea how that can happen as I'm not aware of any old copy still residing on my system.  Or does ExifTool extract into other system folders than C:\Users\MyName\AppData\Local\Temp\parMyName\cache-exiftool-9.7x as well?

Win 8.1 64bit, using ExifTool through piping.

Thanks
-Uwe