If the LabQuest App has a lot of data (as in more than 10 000 points), there may be a delay in connecting the LabQuest to a computer, causing Logger Pro to fail to find the LabQuest. If this happens, disconnect the LabQuest.
If you don't want to keep the data, choose New from the File menu and discard the data. Then connect to the computer and launch Logger Pro.
If you want to keep the data, you need to save them in the LabQuest App. Choose Save from the File menu, and give the new file a name. Then choose New from the File menu to clear out LabQuest App.
Connect the LabQuest to the computer and launch Logger Pro. With no data in LabQuest App, the connection will succeed if the initial problem was due to too many points in LabQuest App memory. To view the saved data in Logger Pro, use the LabQuest Browser to open the file you just saved on the LabQuest.
TIL 1785: LabQuest won't connect to Logger Pro.