Maybe this has happened to you: you’ve created several LabVIEW classes, monkeyed around with the class properties (inheritance, perhaps), and then, seemingly out of nowhere, one of your classes is now locked. LabVIEW will claim:
The library is locked for the following reason(s): This LabVIEW class is loaded in multiple application instances. Classes must be in only a single application instance to be edited.
Nonsense. You’ve never used this class anywhere else! Before you start wondering if you suffer from multiple personality disorder, try this little trick:
- Open up the relevant LabVIEW project and navigate to the class in question. Notice the key icon beside the class name.
- In Windows Explorer, navigate to the offending .lvclass file.
- Open the .lvclass file.
- Save everything.
- Notice how the key went away? Good.