Soyus had TWO fatal accidents, one in 1967, the other in 1971. Both total crew loss.
The 1967 one was a first test flight with only one occupant. There were huge problems with the attitude sensors, so the first landing attempt failed. The second attempt resulted in parachute failure, as the main parachute didn't deploy. The landing rockets set the ship on fire, killing the cosmonaut inside.
linkThe 1971 one involved problems with the hatch of the re-entry module. The crew (3) was found dead after landing. After this accident they flew with 2 persons for a while.
There were loads of other inflight and landing emergencies, some quite serious...
For example:
Souyz will NOT float, as they discovered after a landing on a frozen lake in the south. The capsule began to fill with water, and the CO2 remover ran out of power. They had to wait half a day before the weather got better (temperature-induced fog, outside temperature -22C, while the saltwater lake was a little frozen-over) and the helicopter could pull the capsule out of the lake.