Hey everyone! I literally just made an account to post my fix for this so here goes.
I tried all the usual fixes for this error after researching for a few hours to no avail, some examples of what I tried were:
Unplugging and replugging everything
Updating GPU drivers
SteamVR re-Install
Disabling SteamVR direct mode (no idea why that was suggested as a fix)
Using the orange hdmi and usb cables plugged directly to the PC I/O
None of the above worked.
Until I stumbled across a video of how to replace the vive headstap and found that there are cables you can remove at on the HMD itself.
I soon noticed that once I had taken off the cover plate that holds the cables in, the HDMI cable was loose.
After pushing the hdmi cable firmly into the HMD and placing the cover back on, a quick reinstall of SteamVR and reset of the headset made it detect! Hell yeah!
If this fixed your issue please comment! I would love to know that I helped solved others issues :)
Enjoy gaming in VR!
-emjaay
