An electronic device may have a hard disk drive mounted diagonally within a housing. Electromagnetic interference shielding structures may enclose the hard disk drive. The shielding structures may include conductive elastomeric structures. A printed circuit board may be mounted diagonally in parallel with the hard disk drive. Connectors on the printed circuit board may be angled away from the printed circuit board at a non-zero angle and may be retained against the housing with a slide and lock connector retention member. An accelerometer may detect when the device is tipped over so that control circuitry may protect the hard disk drive. A fan may cause air to flow upwards on one side of the device and downwards on the other side of the device. The housing may rest on housing support structures with angled air vents and integral elastomeric feet.