Fatal Error:

[JohnEmory]

Exporting a batch of blog posts (ProBlog to be specific) dating back to 2013, >100 posts.
Get the following error white page error of death:

Fatal error: Call to a member function getFileID() on a non-object in /home/primary/public_html/updates/concrete5.6.3.4/concrete/core/models/attribute/types/image_file.php on line 30.

Got error first in c5.6.3.3, then recalled there was an update so did that, same error tho.

[Mesuva]

I hit this as well. I was able to solve it by editing /concrete/core/models/attributes/types/image_file.php, changing the exportValue function to:

public function exportValue($akn) {
        $av = $akn->addChild('value');
        $file = $this->getValue();
        if ($file) {
            $av->addChild('fID', ContentExporter::replaceFileWithPlaceHolder($file->getFileID()));
        }
    }

I think this is just cases where the original file is deleted, so it's not really going to lose data - it doesn't have the file anymore to reference.

[madesimplemedia]

I have this issue too in c5.6.3.3. Mesuva I tried your code change but still an issue.

[buurvrouw]

This solution works for me, thanks mesuva!