Background
Since October 2018, we have received the following feedback from users:
The first situation: For Foxit PhantomPDF which is older than version 10,use of Foxit Creator addin in Firefox to convert web pages does not work properly, the pdf file cannot be created, and the process was stuck in Download Status window as the below one.
The second situation: For Foxit PhantomPDF V10 and above, use of Foxit Creator addin in Firefox to convert web pages receives the error message 'The engine files for conversion could not be loaded due to the Firefox Launcher Process.
Cause
Mozilla Firefox will soon block the injection of DLLs by antivirus applications and other third-party programs in an effort to improve stability, security, and privacy.
Firefox Nightly, the cutting edge version of the Firefox browser, blocks DLL injections already. The feature will be integrated in Beta and Release versions of the Firefox browser when they hit version 66.
Firefox Beta will hit version 66 on January 29, 2019, and Firefox Stable version 66 on March 19, 2019 according to the release schedule.
How do you know whether the protective feature is enabled already? That's easy. Just open ‘about:support’ in the browser's address bar and check the Launcher Process listing near the top.
If it states enabled the protective feature is active; if it states disabled or is not present, it is inactive.
Solution
Now you can try the below workaround to resolve the issue.
1. Go to about:config
2. Search: browser.launcherProcess.enabled
3. Double-click on it to set it to False.
Note that the link returns the preference only if it exists.
Related article:
How to Enable Foxit PDF Creator Plug-in in Browser?