Well, yes...we know a single click doesn’t do anything except highlight the file.
Double-clicking to open a file is common. I believe what is happening is either your file association is set to your older version or, what Adrian mentioned above.
Certainly, when a newer software version is installed, the file association is SUPPOSED to be updated. However, there are plenty of scenarios where this can fail.
You will eliminate your problem by uninstalling the old version. In some rare cases, you may need to re-install the new version to get the file association to “lock in” automatically (although you SHOULD be able to set the file association manually in any case).
If you are concerned about losing your Tool Database, you can migrate the existing one from the older software version to your newer version prior to uninstalling. By the way, I keep a safe copy of my Tool Database on hand anyway.
-ShopBot Buddy PRSAlpha CNC