so i was playing on this world for quite some time now and i just noticed these chunk errors nearby my base and it got me kinda worried cuz they werent there yesterday and idk what caused them. i heard that they could be caused by lack of memory in the pc but my local disc says theres still 19gb of free space so idk what could have caused this. im playing on minecraft optifine 1.15.2 can someone please tell me whats going on and how to fix it?
Try right-clicking on the folder for the world (located in %appdata%\.minecraft\saves) and click on "restore previous versions" - if you are lucky there will be a backup, possibly more than one, that was automatically made by Windows (IDK about other operating systems). Note that this option may not be enabled and/or it doesn't make regular backups - you still want to make regular backups of anything you think is important - this also means to a separate location/device, not just making a local copy.