Very surprising result of a crash

Originally posted by Tahnval: 7DTD saves piecemeal during play because the save files are so large. There's only a full save when you exit the game. It's notorious for handling crashes badly. If you've had multiple crashes and no problems in 10 years, you've been extraordinarily lucky.

This is mostly incorrect.

The save is made up of a large number of small files. World data is read and written live as you move around. Character data is saved extremely regularly. Vehicles and electrical data is saved about once every two minutes. Each of these actions is being done with their own individual files, along with writing periodic backups of the files.

Which is why your game typically gets corrupted during an improper shutdown. Any file actively being accessed can be corrupted.

Originally posted by Tahnval: The whole gameworld usually becomes corrupt after a while, too, but that doesn't attract as much attention because not many people play the same playthrough for long enough for it to be a major issue. I've found corruption of the gameworld usually starts at some point past day 70.

This is false. If your system is capable of maintaining the data stream, and you have properly excluded both the client and save folders from security software, you will never have this issue.

However, if you are exceeding the capabilities of the client, or your computer system, then there will be issues where the data is not able to be saved properly. Usually because of a bottleneck in either CPU processing, RAM availability, or disk access I/O speeds.

So say you only meet the minimum hardware spec, and are playing with a slow platter drive or external drive. Your system may struggle with even the standard 8k map, and you will run into corruption because your system cannot keep up with the data access rates the client requires.

Originally posted by Tahnval: Ryzen 7 5700X, Radeon 7800XT, 32GB DDR4-3600, Samsung EVO 870 SSD (I have 4 internal SSDs, but that's the one 7DTD is on). That's well above minimum spec. And I always, and I mean always, get that problem. Today, it was at game day 61. It's not unusual - people who make series of gameplay videos on 7DTD mention it.

Because it just happens to you, does not mean it happens to everyone. I regularly play past day 150, and have had servers run into the thousands.

What drive is your save data stored on?
Did you fully exclude the save folder and game client folder from security software?
Did you clean your system of bloatware?
The list goes on. Just because you have a mid-grade CPU with a high-end GPU does not exclude you from having bottlenecks caused by software or bloatware eating up resources. Remember, the game doesn't give a ♥♥♥♥ that you have a 7800XT. The game is CPU-bound, so if your CPU is tied up with other stuff that will cause you a problem.

I take what "people who make series of gameplay videos" with a grain of salt because I have seen the setups a lot of these people are running. It works great for single-core applications but falls on its face when a program like 7 Days goes to use half their CPU cores.

Originally posted by MoistGamer:

Originally posted by SylenThunder: properly excluded both the client and save folders from security software

What does this mean - I've never done this and also never had a crash outside of a power outage. Should I be doing that

It is what we call "standard operating procedure". It has been stardard for gaming for over 30 years now. I cover it in detail in the Support FAQ thread on the official forum, and have also copied it here.
At best, you will only experience a slight degradation in game performance. However it is also very possible that a game client file, or act of saving data can trigger a false positive which will end up corrupting the affected files.
If you hear someone complaining about their ping to a server suddenly spiking to 3000ms or similar, there is a 99.9% chance that it was because their security software was locking the data packets so it could scan them.
And people will say "I don't have any software installed". And they would be wrong. Microsoft Defender/Security Essentials is on by default and cannot fully be turned off without replacing it with a different product.