Reply To: Alt M is not working
@waylow is probably right: your icons also look old. 
You are probably using a version from before May 6th 2019, when Remove Doubles was changed into Merge by Distance (and some Icons changed):
@waylow is probably right: your icons also look old.
You are probably using a version from before May 6th 2019, when Remove Doubles was changed into Merge by Distance (and some Icons changed):