Neither Quite Software nor Enfocus have released their Acrobat DC-compatible versions of their plug-ins yet.
The MacOS version of Acrobat is now 64-bit and as such, the older versions of the plug-ins will not work at all. Don't even try installing them!!!! I believe Enfocus is planning a product release very soon that will be compatible with Acrobat DC. Quite Software is also working to complete their Acrobat DC-compatible plug-ins.
- Dov