Coffee Machine Brew Unit Not Fitting Back In

Why won't my coffee machine brew unit fit back into the machine?
The brew unit or the machine's internal drive may not be in the correct position for installation. This can happen if the machine was operated while the brew unit was removed, the unit was moved manually during cleaning, or the machine was interrupted partway through a cycle. Do not force the brew unit into position, as this can damage the drive or brewing mechanism.
How do I get the brew unit back into the correct position?
First check that the brew unit itself is correctly assembled and positioned for installation. If the machine's internal drive appears to be in the wrong position, some machines can reset themselves by refitting the drip tray and grounds container, closing the service door and allowing the machine to complete a normal start-up and shutdown cycle without the brew unit installed. However, this procedure varies by machine, so use model-specific instructions where available.
Why won't the brew unit fit after I've cleaned it?
The brew unit may have moved out of its installation position while being handled or cleaned. Check that any moving sections have returned to their normal position and that nothing has been incorrectly assembled. Also inspect the brewing compartment for loose grounds or other obstructions that could prevent the unit from sliding fully into place.
Should I force the brew unit back into my coffee machine?
No. A correctly positioned brew unit should normally install without excessive force. If it stops partway in, remove it and check its position rather than pushing harder. Forcing the unit can damage plastic guides, gears, the brewing mechanism or the machine's internal drive.
Can the machine's internal drive be in the wrong position?
Yes. The drive mechanism moves the brew unit through different positions during grinding, brewing and waste disposal. If the machine loses power or is interrupted during one of these movements, the drive may not return to its normal resting position. The brew unit and drive then no longer align, preventing the unit from being reinstalled.
What should I do if the brew unit still won't fit back in?
Stop attempting to install it if you've checked for obstructions and confirmed that the brew unit is correctly assembled. The next step should be model-specific guidance, because brew-unit reset and installation procedures differ between machines. If the brew unit or internal drive cannot be returned to the correct position using the approved procedure, the drive mechanism, position sensing or brewing assembly may require further diagnosis.