I'm running Windows 8.1 and have tried almost everything to get the LyX spellchecker working. I know that there have been questions asked before on this site here and here. I've tried almost everything posted on these two answers. I tried to change the Hunspell paths to LyX 2.1/Resources/dicts and to MikTex 2.9/hunspell/dicts and copying the LyX dictionaries to C:/dicts. I even tried reverting to LyX 2.1.3 to see if it would help and it did not. They only way I got my LyX document spellchecked was copying my document to dropbox and using LyX on my linux (Manjaro) virtual machine. Even under Manjaro I think I had to use the enchant spellchecker engine to get spellcheck working. I thought I would try that in Windows but there are no binaries available for enchant. I would really like to get this working because I like to write my lab reports in LyX.