Cannot remove 0.1 sec trailing silence

I am using Audacity 2.1.0 with Windows 7, and I have been editing mp3 files. In order to maintain a flow of music, I’d like to remove as much as I can of the silence at the start of each track. However, I always seem to have a 0.1 second silence left at the start of the track. If I select the silence and delete it, then export the file, the 0.1 second silence is inexplicably back again in the exported file. Is there a way to override this?

No. It’s a limitation of the MP3 format.
“Encoder/decoder overall delay is not defined, which means there is no official provision for gapless playback”

Try using another format such as WAV, FLAC or Ogg.