My goodness, my adding a HD500 to become a basic audio interface to a mac (High Sierra) was a challenge. I am adding this as a public service in hopes of saving people time. I installed Line 6 Monkey and almost smoothly adding all the drivers etc, but when it came to the flash update, it wasted a lot of time. I alternated using the downloaded file to downloading it fresh, to unplugging the HD500 to restarting the mac to nav R power on to nav down power on etc etc.Reading, trying, reading, trying.... It kept saying the new flash was installed on the Monkey, then it just stopped. The SOLUTION was to roll back to the 2nd last recent Flash version. I have a Helix too and have gone through most POD products. My question to Line 6 is why leave glitchy software/ firmware in circulation. It makes me want to get a Fractal FM3. haha (I'm on the waiting list). Anyways, hope it helps someone out there save some time.