I think it's something with the GrovePi's firmware.
So I'm suggesting you follow the 3 steps found in the next screenshot and after that, please make a screenshot of the terminal that's opened in the background and post it here (aka
Update in progress - Do not close this window!)
Then retry with
i2cdetect to see if it's functional after you reboot the system.
Seeing that you only have a sensor at hand, I can give you an unofficial library for that one in particular (the
high temperature sensor from seeed). Since it's unofficial, there might be problems with it.
You have to do the following:
$ cd ~/Desktop
$ mkdir unofficial
$ cd unofficial
$ git clone -b develop https://github.com/RobertLucian/GrovePi.git
$ cd GrovePi/Software/Python
$ cp grovepi.py grove_hightemperature_sensor/
$ cd grove_hightemperature_sensor
$ python3 high_temperature_example.py
Please, take a look in the example program so you know what you have to do. You'll have to use
A0 analog port with the sensor.
By the way, you can insert the tip of the sensor in water if you want to measure the temperature.
Apropo, only the tip of the sensor senses the temperature.