Sometimes, when switching between offline mode and online mode, player's uuid will change. Minecraft uses uuid to save the inventory. So you might need to check your previous logs to see the previous uuid, and rename the inventory files ([uuid].bat) into the new one.
QH
Sometimes, when switching between offline mode and online mode, player's uuid will change. Minecraft uses uuid to save the inventory. So you might need to check your previous logs to see the previous uuid, and rename the inventory files ([uuid].bat) into the new one.