Q:

I think "Thank you for letting me knows" is incorrect.  Am I right? 

Microsoft Word corrected my text to read 

Thank you for letting me knows

so now I'm a little unsure that know is correct and knows is incorrect. 
I usually work it out by the ‘which sounds right’ method. 
And the phrase "Thank you for letting me knows" just sounds wrong. 
Shouldn't it be "Thank you for letting me know"? 

What am I missing here? 

A:

Yes, "Thank you for letting me know."  is correct. " Know" in that sentence should be an infinitive (without 'to') and not conjugated, which MS Word did.