Some Magento extensions don’t play well with Searchanise:

• SEO Layered Navigation breaks the instant search widget.
  
  Use this workaround.
  Note

  Searchanise’s full-text search will not work with this workaround.

• SEO Suite Ultimate breaks the instant search widget
  
  Use this workaround.
  
  Note

  Searchanise’s full-text search will not work with this workaround.

• Lesti::Fpc breaks the instant search widget
  
  Use this workaround.

  Note

  Searchanise’s full-text search will not work with this workaround.

• Extendware Full Page Cache log you out from the Magento admin panel when you go to Catalog → Searchanise.
  
  Disable Primary cache in the Full Page Cache settings to work around this one.