You have not provided any information about the device you are working on or what you have done so far.
Usually this message is displayed when you are part way through a process and you start it again.
If the process is underway, wait until it is completed and then just start again, overwriting the earlier attempt so as to ensure there are no errors in the first attempt.
If your earlier attempt is not progressing you may need to turn off your device to be sure you have stopped any processes currently underway.
Once the device has restarted, first use your devices inbuilt uninstall programme or mechanism (if it has one) to uninstall whatever is there now. If for example you are working on an Android device you will need to go to "Settings" then scroll down to "Apps" and after clicking on that, scroll down to "iGO" and take the "uninstall" tab.
That will uninstall the programme but not remove it from the device. You must now do that.
Use either an internal file management programme like "Total Commander" or similar, or use an external device like your computer to search your device for the iGO folder which will still be there. Delete that folder altogether.
Now start the installation process again.
If the process outlined does not suit your device, please supply a full description of your device, what you have done and what you would like to do. With out that you can not expect any serious help.