Pro Tools 10 utilizes the old PACE iLok driver system, which conflicts with High Sierra. You need to replace the start-up authorization check.
Official Status: Unsupported by Avid.
Practical Feasibility: Possible with significant limitations and workarounds.
Primary Challenge: Pro Tools 10 is a 32-bit application; macOS High Sierra is the last version to support 32-bit apps, but Avid never certified PT10 beyond OS X 10.8.5 (Mountain Lion).
Target Audience: Legacy session access, users maintaining old plugins unavailable in 64-bit. install pro tools 103 10 on high sierra
Avid’s installer certificates expired years ago. High Sierra will refuse to run the package if it thinks the date is “too modern.” Pro Tools 10 utilizes the old PACE iLok