How to fix PyVISA "No module named 'serial.tools'"

Problem:

You want to use an ASRL (serial) instrument in PyVISA, but when you run

python3 -m visa info

you get this output even though you have serial installed:

ASRL INSTR:
   Please install PySerial (>=3.0) to use this resource type.
   No module named 'serial.tools'

Solution

You have installed serial but you need to install pyserial - they are not the same!

First you need to remove the system package python3-serial if installed. Example for Ubuntu/Debian:

sudo apt remove python3-serial

and also remove the pip serial package if installed

pip uninstall serial

Then install pyserial:

pip install -U pyserial

You can check if PySerial is installed properly using

python3 -m visa info

It should show you

ASRL INSTR: Available via PySerial (3.4)

once pyserial is installed correctly!

***Note:***The commands above are for Python 3.x. In case you are still using Python 2.x use pip2 instead of pip and use python-serial instead of python3-serial as APT package name.