It is vital that any use of the "Aardvark Open" block is accompanied by an eventual call to the "Aardvark Close" block. Otherwise the LabVIEW process will hold the Aardvark handle open and subsequent runs of your VI will find that the Aardvark handle is in use.

If your VI stops unexpectedly due to a bug (or you happen to terminate a debug session before the "Aardvark Close" block is executed), it is very likely that the Aardvark handle has not been released. You may manually release the Aardvark adapter by opening the front panel for "Aardvark Close" and closing the appropriate handle numbers manually. Aardvark handle numbers start from 1. If a close is successful, the "error out" field in the "Aardvark Close" front panel will not show any errors. If the handle number is invalid (because it is not currently associated with any Aardvark) the "error out" field will list an error.

NOTE: If an adapter is held by LabVIEW, the first execution of "Aardvark Close" with that handle ID will complete successfully, and a subsequent execution with the same handle ID will list the "Aardvark invalid handle" error.