Started up tekkit classic version 3.1.2 in single-player, and I was trying to mine. After mining stone blocks repeatedly, with a diamond pickaxe, I noticed that blocks were not dropping. Tried with dirt, still nothing. When I try to drop an item, it also disappears.
I tried deleting Technic Launcher, and re-downloading, and it but I still have the same problem. I am having this problem across all single player worlds.
Is there anything I can do to fix this?