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:
- Select Edit, select Preferences, select Security (enhanced).
- Select the Sandbox protections checkbox.
- Remove the Enable Protected Mode at Startup checkbox.
Source: Adobe forum
*Note: The letters and numbers after application at location may vary.
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