"undefined reference" error please help

I have a project that was on hold for couple of months waiting for some parts, I finally got the needed parts and when I got back to work on it something has been changed and I don’t understand what is the problem, The project contains an Arduino Mega with an Adafruit BNO055 sensor which worked perfectly until now, when compiling the project I get the following error:

Compiling debug version of ‘wheelie_panic_break’ for ‘Arduino/Genuino Mega w/ ATmega2560 (Mega 2560)’
wheelie_panic_break.cpp.o:In function __static_initialization_and_destruction_0 wheelie_panic_break.ino:undefined reference to Adafruit_BNO055 Adafruit_BNO055(long, unsigned char)
collect2.exe*:error: ld returned 1 exit status

I’ve reinstalled the the lib from github and made sure that its included in the header files:

#include <Adafruit_Sensor.h>
#include <Adafruit_BNO055.h>
#include <utility/imumaths.h>

but that didn’t solve the problem, what is it I’m missing here?

Any thought will be highly appreciated!!!
Many thanks in advance,
Best,
Ram

Which version of the IDE are you using ?

Should the library folder have -master in its name ? I have lost track of the recent changes to how the Arduino IDE finds library files. It used to be that the library folder name had to match the.h and .cpp files but that requirement may have changed.

@UKHeliBob, thank you for your reply!

currently I manage to successfully compile the sketch, had to remove "-master" from the folders names and also I've downgraded the IDE to 1.6.9 from 1.6.10

I have other issues when uploading the sketch now (using visual studio vMicro) but thats for a different thread :slight_smile:

I am working on the Battery management system . My code is to interface the BQ20Z45 with arduino through SMBus communication. I am stuck with this error. Can you please help me.

Arduino: 1.8.9 (Windows 10), Board: "Arduino/Genuino Uno"

C:\Users\OMGANE~1\AppData\Local\Temp\ccMuSMML.ltrans0.ltrans.o: In function `loop':

C:\Users\om ganeshaya namaha\Documents\Arduino\TESTING\example\BQ20Z45/BQ20Z45.ino:23: undefined reference to `BQ20Z45::GetTemp()'

collect2.exe: error: ld returned 1 exit status

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Please post your complete program and details of the libraries that you are using

Is that the full error message ?