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To run SystemCheck, you should download the latest supported version of Java for your browser (see Browser Dependencies).
Oracle disables an existing version of Java when it releases a new version that contains critical fixes. Failure to download the new version of the Java plugin results in the following error because the Java applet cannot load (click to enlarge):
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System Check is Unable to Run
To run SystemCheck, you must allow it to fetch content from URLs specified in the Firewall/Proxy Servers/Content Filtering section of the System Requirements page.
Failure to access these URLs due to browser security settings causes SystemCheck to display the following error (click to enlarge):
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