Problem:  Adobe Reader XI is installed and was used to open some PDF files, and Microsoft Windows displayed this type of error message*:  unknown software exception (0xc0000409) occurred in the application at location 0x0041240b

Solution:  Open Adobe, and then do the following:

  1. Select Edit, select Preferences, select Security (enhanced).
  2. Select the Sandbox protections checkbox.
  3. Remove the Enable Protected Mode at Startup checkbox.

SourceAdobe forum

*Note:  The letters and numbers after application at location may vary.

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*Content is subject to change. For the most recent version, visit the Help Portal.
Printed on: 1/21/22