Happens when I try to load an old save.

The mod Auto Trash (5.1.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event AutoTrash::on_configuration_changed
Unknown sprite "item/ltn-combinator"
stack traceback:
AutoTrash/gui.lua:1194: in function 'open_status_display'
AutoTrash/gui.lua:814: in function 'init'
AutoTrash/control.lua:127: in function 'init_player'
AutoTrash/control.lua:137: in function 'init_players'
AutoTrash/control.lua:251: in function <AutoTrash/control.lua:181>
stack traceback:
[C]: in function 'newindex'
__AutoTrash/gui.lua:1194: in function 'open_status_display'
AutoTrash/gui.lua:814: in function 'init'
AutoTrash/control.lua:127: in function 'init_player'
AutoTrash/control.lua:137: in function 'init_players'
AutoTrash/control.lua:251: in function <AutoTrash/control.lua:181>

If you need save please let me know, because that save is very large.

It should be fixed in the latest update. If not you might be better of disabling Autotrash, load and save the game and then reenabling Autotrash. You'll loose your configuration but then it should work.