This version marked the deep integration of Adobe Document Services (precursors to Adobe Document Cloud). Features included:
Protected Mode sandboxes Reader XI, but on modern Windows, this feature frequently triggers 11001. adobe reader xi 11001
If you cannot open Reader to change this setting: This version marked the deep integration of Adobe
Despite the security risks, queries for Adobe Reader XI 11.0.01 remain common for several reasons: If you cannot open Reader to change this
If you must keep Adobe Reader XI for legacy internal forms/scripts that break in newer versions:
Warning: Exploits exist for Reader XI. Do not use it to open untrusted PDFs from the internet.