Diskussion:Flashforge Inventor II
Fixing Stuck Filament flashforge Inventor II and Flashforge Finder
If there is not coming any material out of the extruder, you might consider following these steps.
1. Abort the print.
2. Then try to preheat the nozzle (see Figure 1). By doing this you will detect if there is any material in the extruder at all. You will notice this if any material gets out of the nozzle during the preheat. You will then be good to go and try to start the print again. However, if you have the same problem again or if no material is going through the nozzle during the preheat. It is then suggested that you should have to take the nozzle head apart which leads to the next step.
3. This step will force you to disconnect the printer and place it on a table in Makerspace. This step is just a precaution to make sure that no other printer gets damaged during the process of fixing the one you are working on.
4. By assuming that your print didn’t work in step 2 then to make this work, connect the power cable again and follow the instructions in this video linked below while fixing the problem on a table in makerspace.  You might as well find this link useful to: 
Figure 1. The preheat icon is the one in the middle