BibLaTeX in LyX 2.1.0 with MiKTex on Windows 7: ! Package biblatex Error: Incompatible package 'backref'

I tried the same, had the same problem with LyX2.1.4 on Win7. Followed all the above no luck. Been here many times before with 'hidden' LyX stettings clobbering imported LaTeX :-(

Solution: |Documents>Settings>PDF Properties>[Hyperlinks]Backreferences:[Off]

Typesets exactly as it should :-)

Not quite, because the backlinks are disabled unless you select |Document>Settings>Bibliography>Processor: to work with bibLaTeX as stated in the previous comment by Torbjørn T.

The universal solution would be for LyX to display all the LaTeX settingings it 'applies in the background'. You can |View>Source Pane>[Preamble Only] but you still have to search for where it is set! B.T.W. if you only change the menu biber setting LyX will NOT re-typeset the document to show it works (LyX2.1.4-Win7). You have to type something! :-(