#1
If I put my finger on the second-highest fret of the D string, it plays a half-step too high. The last fret on the board is interfering, but it only happens with the D string. All other frets on all other strings are just fine. The bridge is all set right, the neck is set right, it's just this one fret that seems to stick up just barely too high in that one spot. What can I do about this?

Chinese Squier Stratacaster. Surprisingly this is the only problem it has.
Agile AL-3010SE Goldtop
Carvin 4-string kit bass
Stradivarius copy cello
-><-
#2
1. File the last fret down a bit in that spot, if you know what you are doing. Otherwise have a tech do it.

2. Realize that you likely never have or will play a song using the 21st fret on the D string. :p
#3
There are some videos on youtube about filing an individual fret.

I never had much luck filing just one fret. I have had success leveling the entire neck and have done it to just about all my guitars. It takes patience and some balls to do this. There are instructions on the web. Google "Ron Kirn level neck frets".

As JGM58 said, you probably will never use that fret so you might just forget about it.
But if you are using it then you have to fix it I guess.
#4
Thanks for the replies, guys. I'll check with the guitar professor on campus and see what's involved with filing it down.

I found out it was too high when I was playing a solo
Agile AL-3010SE Goldtop
Carvin 4-string kit bass
Stradivarius copy cello
-><-
#5
Since it is the highest fret, your filing doesn't have to be as precise as it would for any of the other frets, since there is no risk of getting it too low in relation to the next highest fret. I'm guessing you haven't got much in the way of specialised tools, so I would suggest you make a fretboard mask out of aluminium drink can. Just get a piece about 3/4" wide and 2 3/4" long and cut a slot in it with a pair of scissors, wide enough for the fret to show through for filing. A small triangular file will work well for lowering and crowning, and you can finish it with abrasive paper and then metal polish, using something like a wine bottle cork as a hard pad for sanding a polishing.
#6
Filed it down today while changing the strings. It all feels much better now and it works properly!
Agile AL-3010SE Goldtop
Carvin 4-string kit bass
Stradivarius copy cello
-><-