I had a print of about 3 hours stop half-way through. Figured it was a clog or filament jam of some sort. Took the filament out, checked the gear for blockages -- PETg often seems to get a stripped & bent wad right at the gear for me -- and it was OK. Got things back up to temperature, tried to insert filament -- and it wasn't gripping. Further inspection revealed it wasn't turning -- though the motor was humming as if it was.
So, I checked this forum
![Very Happy :D](./images/smilies/icon_e_biggrin.gif)
![Shocked :shock:](./images/smilies/icon_eek.gif)
![Confused :?](./images/smilies/icon_e_confused.gif)