条件・譲歩N1
〜ても知らない
don't blame me if... / if you... then don't complain
Structure
V-て形 + も知らない
Explanation
V-te + も知らない: if you do it, the consequences are your own; used as a warning.
Examples
遅れても知らないよ。早く支度して。
Don't blame me if you're late—hurry up and get ready.
無理をして倒れても知らないからね。
If you overwork yourself and collapse, that's your problem.
Note
Colloquial warning: the speaker disclaims responsibility. Also ても知りません.
Related Grammar
〜ても知りません〜ても構わない