Definition - What does Unrecoverable Error mean?
An unrecoverable error is an error that occurs during the execution of a code or a program that has not been registered before and no retries can correct or undo the error. Usually an unrecoverable error freezes the system and it must be rebooted to work again.
An unrecoverable error is also known as a user-mode fault or user-mode exception.
Techopedia explains Unrecoverable Error
Unrecoverable errors are usually caused by of programs or applications that run in user-mode on a computer. User-mode run processes are not given direct access to the memory, rather they use a virtual space assigned to them by the system. Since they are basically isolated from direct access to memory, they do not interfere with the resources and hence do not compromise of the integrity of a system. But at the same time they are at a huge potential to cause an unrecoverable error if they try to read or write anything from the system memory. This causes an exception call and the whole system either freezes or reboots.