I had built a soil house and cleared a huge area of trees and grass, planted some crops and had containers full of stuff. I logged out with the save exit option and let it close like it should. Upon logging on to play today. Everything was reverted back to before I had built my house and cleared the area. The only thing that didn't change is the berry bushes I had planted and my inventory items were still on me. I did not use the prospecting pick, hadn't made it that far yet and I've only been playing long enough to only have version 1.12.6.
I exceed the system requirements and am running on a fresh clean re-install of my system with fully updated drivers for everything. Windows 10 home pro edition, 4.3 ghz AMD ryzen, 16 gb ram 3600 mhz, geforce gtx 1660 ti.