new update unalived half my sim population & what do i get in return? nothing.

While I understand the frustration, deleting a save is not the answer (especially if you're not backing up your game regularly).

You can always quit without saving and wait for a fix, then roll back and recover an earlier version of the save in question (there's an option to easily recover earlier saves any time you click on a save in the load menu). You might lose some progress, but at least you won't lose everything you've worked so hard on.