Logger Pro does not connect to the interface and reads "No Device Connected" in the toolbar.

Logger Pro will display the message "No Device Connected" in the toolbar when a device such as LabQuest, a Go! device, or a Spectrometer, cannot be found. Below are troubleshooting steps to solve the most common problems.

If you have multiple computers and interfaces, with some of them working and some not, try methodically switching interfaces, cables, power supplies, and computers to see if the problem is with a piece of the hardware or with the computer. The best test to do is to take one of your completely working stations, and try swapping in a different interface, then a new connector cable, etc. If you can trace the problem to one of these pieces, we can probably repair or replace that part.

1) What version of Logger Pro are using? To find out, open Logger Pro and choose "About Logger Pro". The exact version number will in the About screen. If you have a version of Logger Pro older than 3.8, you may need to update in order to get the latest drivers. The free upgrade from previous version of Logger Pro 3 is available at: http://www.vernier.com/tech/lpupdates.html.
Please note that not all computer operating systems work with the latest version of Logger Pro. For a summary of which versions of Logger Pro work with the your OS, see:
http://www.vernier.com/tech/lpupdates.html#older_os

2) Check all of your cable connections. It could be that the device really is not connected. Make sure that one end of the cable is completely plugged in to the interface and the other end is all the way into the computer. It is possible that a USB cable is bad. Use a USB cable that you know is good because it works with a different device.

3) Another program is already connected to the device. If two copies of Logger Pro, Logger Lite, or LabQuest Emulator are running at the same time, only one can talk to a given device. Quit the unneeded applications.

4) The LabQuest or LabPro is not turned on, or has low or dead batteries. Connect an AC adapter to the interface. If you are using a LabQuest, make sure it is turned on.

Mac-Specific Issues
The USB port could be mapped to a guest OS. Other applications such as VMWare Fusion Parallels can seize USB devices and forward the connection to a guest operating system (such as Windows or Linux run on a Mac). In this case the device is not available to the main OS. Either quit the guest OS or release the port.

Windows-Specific Issues
1) The most common problem on a Windows computer is that the drivers have not been installed correctly. See: TIL 2102: (Windows) How do I reinstall Logger Pro 3?

2) An older version of the Jungo driver is persisting, usually because of a custom installation performed by a system administrator (such as repackaging the Logger Pro installer rather than using our provided installer). You can quickly determine the version of the active Jungo driver by launching Logger Pro, and choosing About Logger Pro from the Help menu. Look for LabPro driver version number. The correct version for Logger Pro 3.8 is 9.210. If an earlier version is present, Logger Pro will not be able to find the LabPro or LabQuest, but the driver will show as running normally in the device manager. The solution is to uninstall the Jungo driver from the device manager, and then reinstall Logger Pro 3.8 or newer.
See: TIL 2501: Are the device drivers installed correctly? (For Windows with LabPro, original LabQuest and LabQuest Mini)

LabPro Specific Issues
See: TIL 2098: Logger Pro can not connect to LabPro

LabQuest Specific Issues
See: TIL 1785: LabQuest won't connect to Logger Pro.