I recently purchased the PICO5444D.
My OS is Ubuntu 16.04 LTS
After installing the picoscope SW (using the instructions at https://www.picotech.com/downloads/linux) I connected the device to the computer, exec picoscope, and got the message:
No suitable device found.
I ran the script:
/opt/picoscope/share/doc/libps5000a/usbtest
and got :
Pico USB device found: /dev/bus/usb/001/006
- It belongs to root (which is not you) who has permissions rw-
- The members of group pico (which you are in) have permissions rw-
- Everyone else has permissions r--
- You can write to this device and so will be able to use it.