Has this ever worked? What changed? You recently purchased a used Digilink interface... did this ever work before that? Does it work with that newly purchased hardware disconnected?
Do you have an ASIO interface in the computer? Does Pro Tools work OK with that?
Have you searched DUC for help? e.g. Avid Link is a steaming pile of buggy bloatware. There is advice all over DUC to uninstall it. Why would you not do that? Uninstall the collaboration mess while there as well.
Avid documents HD drivers are a separate install. Kinda buried, but see the Release Info doc e.g.
https://avid.secure.force.com/pkb/ar...6-Release-Info. Make a habit of reading all the release notes/release info docs.
Is your computer fully optimized? Every last thing done no matter how inconvenient?
As for troubleshooting start by reading "help us help you" up the top of every web page.
Troubleshooting Digilink systems problems related to Digilink card/interface etc. typically starts at:
o Trashing prefs
o Running Digitest
o Often you'll end up simplifying the Digilink system as much as possible, one card (well HD Native only has one), one cable, one interface, sync boxes removed etc. You recently purchased a used Digilink interface with bits missing/removed, I'd not trust that at all to begin with. Remove all other necessary peripherals and crap from the computer.
o Uninstalling HD drivers and reinstalling latest ones, being careful to reboot.
What troubleshooting have you done? If you are engaged with Avid support enough to have a negative opinion about them they must have had you doing something... what exactly?
Got a Avid support case number?
What you are saying about support is hard to follow/does not make sense, do you or do you not have an active support plan? If you have one it will say in your Avid account, you file support cases here:
https://www.avid.com/learn-and-suppo...-music-support. If you don't have a current support plan active you need to either upgrade to one or purchase an ASC, certainly need to do that to get a phone support case going. As you are buying all this used Digilink peripherals and HDX cards and don't seem super familiar with some of the details/installation etc., you *need* an active support plan. Pro Tools Ultimate/Flex support plan/upgrade/reinstatements list prices are ~$750, currently around $500 at dealers. Don't buy the wrong thing, talk to a sales rep if not sure.
Post a SiSoft Sandra report.
Don't fall into the trap of wasting days troubleshooting, unless you have a good lead on what is up/Avid is guiding you. Especially if your computer is old/has been upgraded a lot etc... then after trying out the obvious stuff grab a clean SSD or partition on one and do a clean Windows test install, ideally from a Microsoft Windows installer (not an OEM recovery disk or partition full of vendor bloatware or drivers). Bring up Windows with the absolute bare necessities of drivers, do not let Windows search for drivers, install things like GPU drivers yourself. Just to get going. Install Pro Tools... does that work?