In 2nd Edition AD&D does natural Magic Resistance allow a creature to know when it has been targeted by a spell if it resists the spell? (some spells do not make the target aware it has been targeted). I am aware that Magic Resistance works regardless of a target being aware of a casting or not but this question relates to "after the event". Would it set off a tingling for want of a better word?
PHB page 87:
A creature that successfully saves against a spell with no apparent physical effect (such as a charm, hold, or magic jar) may feel a definite force or tingle that is characteristic of a magical attack, if the DM desires. But the exact hostile spell effect or creature ability used cannot be deduced from this tingle.
The only information I could find has to do with resisting a spell via saving throws, rather than magic resistance. We can reasonably assume that magic resistance could be interpreted in the same way. Personally, as a DM, I would be satisfied with this answer, as the RAW, for what it's worth, doesn't cover this exact question. (As with many other questions, hence we have a DM in the first place.)
Essentially, the answer is likely interpreted as yes, but the DM's discretion is the deciding factor.