Before editing the registry or purging systems, establish a clean baseline. Troubleshooting Internal Error 2602 in AutoCAD: Causes and

• Use Process Monitor (Sysinternals) to filter on acad.exe and look for NAME NOT FOUND or ACCESS DENIED on ARX files.
• Check the AutoCAD log file: %temp%\<product name>.log

• Corrupt hatch patterns: Dense or corrupt hatches that render fine on screen but fail during high-DPI plotting.
• Driver conflicts: Outdated printer drivers or the generic AutoCAD PDF driver struggling with complex geometry.
• Hardware acceleration: Your GPU interfering with the plot process.