Bug: Frequent LJME_DEVICE_NOT_FOUND | LabJack


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MiddPhys's picture

Hi I have been attempting to track down what would be causing the labjack T4 to disconnect frequently. I have found that every ferw times I run my program the labjack device does not connect and gives the error code LJME_DEVICE_NOT_FOUND. This alsdo will happen with the example code so I believe it is not unique to my program. The steps I have to then take to resolve the issue are:
Uninstall labjack-ljm
Uninstall LabJack-2019-05-20.exe
Delete LabjackM.dll
Restart my computer
Reinstall labjack-ljm
Close Python then run LabJack-2019-05-20.exe

This resolves the issue briefly. I have to do this atleast once per day if not a few times. I have found that this errror comes about when the usb connection between the T4 and the computer is severed then reconnected. Therefore any time I unplug the device I need to begin this process again. This error will also happen with no apperent cause that I have found. Sometimes if I have left the labjack plugged in but not run the program in a while it will throw the error, or if I leave my program running for an hour or two, come back, stop it, and then restart it, it will throw this error. 

Any advice on how to procede would be greatly appreciated. I can post a link to my code but I'm not sure how useful that would be.

LabJack Support
LabJack Support's picture

An LJME_DEVICE_NOT_FOUND error while the device is plugged in and powered should indicate a USB communication failure rather than an issue in software. I would recommend starting by upgrading firmware using the device updater in Kipling. The current release version of firmware on the T4 is 1.0027:


From there, see our device not found application note and USB communication failure application note: