Uploaded February 2014 | Updated September 2026, 17 hours ago
If you recently started having issues opening Java applets for sites you normally have been using fine your Java may have updated from Update 46 to Update 51 and this new update is the cause of your issues.
In this tutorial I will explain why the issues is happening, how to fix it for the average user at home, and also how to fix it at a higher tier level for somebody in a company/corporation.
The issues persist no matter what settings you change for security in Java and also even if you hit "allow" or "unblock" with your security dialog popups.
The error will tell you to click for details and from there you will see something along the lines of Application Error Security Exception Missing Required Permissions Manifest Attribute In Main Jar.
This error is misleading, it really should say something like "Java will not allow this site to run due to security features, if you wish to manually allow this site please add it to your exceptions list" but yeah that is not happening, so I'll show you how to fix it if this was your issue so you can carry on with what you need to do.
If you recently started having issues opening Java applets for sites you normally have been using fine your Java may have updated from Update 46 to Update 51 and this new update is the cause of your issues.
In this tutorial I will explain why the issues is happening, how to fix it for the average user at home, and also how to fix it at a higher tier level for somebody in a company/corporation.
The issues persist no matter what settings you change for security in Java and also even if you hit "allow" or "unblock" with your security dialog popups.
The error will tell you to click for details and from there you will see something along the lines of Application Error Security Exception Missing Required Permissions Manifest Attribute In Main Jar.
This error is misleading, it really should say something like "Java will not allow this site to run due to security features, if you wish to manually allow this site please add it to your exceptions list" but yeah that is not happening, so I'll show you how to fix it if this was your issue so you can carry on with what you need to do.
