Try this:
* Download the latest dev build (4.0-5511 as of this writing) from the official site: https://dolphin-emu.org/download/
* Make a new folder (e.g. Dolphin_DEV) on your drive (just make sure it's NOT in your 'Program Files', 'Documents' or other 'System' folders) and extract the contents of the .7z 'package' into that folder.
* Create a new empty file named portable.txt inside that folder.
* Start Dolphin, configure it as desired, then close it and start it again.
* Download the latest dev build (4.0-5511 as of this writing) from the official site: https://dolphin-emu.org/download/
* Make a new folder (e.g. Dolphin_DEV) on your drive (just make sure it's NOT in your 'Program Files', 'Documents' or other 'System' folders) and extract the contents of the .7z 'package' into that folder.
* Create a new empty file named portable.txt inside that folder.
* Start Dolphin, configure it as desired, then close it and start it again.