Error Msg
 

I have trouble identifying the problem reporter in the attached error message.

That message indicates that either the Java binary or the epubcheck jar file couldn't be found.

If you've recently installed a new Java version, you might have to add the path to the Java binary to the system path.

To test whether your Java binary can be found open a command prompt and enter the following:

If you get a version number uninstall the epubcheck plugin and download/install the latest version.
Also make sure that you tick the Use Bundled Python option.

If you don't get a Java version number, check the epubcheck troubleshooting section.

If none of this works for you download pagina EPUB-Checker.

Sigil 8.5
 

I am using Sigil 8.5 and the same on another machine which works fine.

Everything seems the same on both machines including the APP data. The attached image shows the setup.

You're welcome to continue using Sigil 0.8.5; just know that fewer and fewer plugins are going to support Python 2 (and support for such an old version of Sigil in general is going to be harder and harder to come by). Since 0.9.0, Sigil has included its own version of Python (Python 3) on Windows and OSX, so there's no need to configure it to use an external Python interpreter. Most new plugins (and new versions of older plugins) are not worrying about staying compatible with Python 2.x any longer. In fact, Python 2 plugin support will soon be removed from Sigil altogether. The reason being that the latest versions of Sigil either include Python 3, or require Python 3 to compile anyway.

Did you open a command prompt and enter:

on the machine that doesn't work?

If so, what was the results?

There is no Java

Is there a built in validation check for epub 2?? Is everything needed included in the install? I don't understand all these plug-ins. What I need is a "FOR DUMMYS" version.

As described in the epubcheck plugin requirements section, epubcheck requires Java and and the Java binary path must be accessible via the PATH system variable.
For more information on fixing this issue, see the epubcheck plugin troubleshooting section.

Not a "built-in" validator, no. But the exact same Flightcrew validator (the validator that was built into Sigil in the past) is available as a plugin and downloadable from the exact same location as the Sigil installer.

There seem to be a jungle of Java downloads!!!
Can you point me to the version needed?

Visit the official Oracle website and click the Free Java Download button to download the universal web installer.

Make sure to de-select the optional Amazon offers or other optional software bundles offered by the installer.

Also accept the offer to uninstall older versions at the end of the installation.

After the installation open a DOS command prompt window and enter:

You should get the following message:

'

That did it:thanks::thanks: