VLC plugin prevents Firefox closing

[Verify_Me]

Hello! My Firefox v33.1.1 has begun to "hang" after closing, continuing to run in memory until firefox.exe and plugins-container.exe are manually terminated. Following Mozilla Troubleshooting guidelines, the 'cause' was found to be VLC plugin v2.1.3 (npvlc.dll), even though I have updated to VLC 2.1.5 on my Windows machine.

If the VLC plugin is disabled, Firefox functions normally, and closes normally. I renamed npvlc.dll and xx.manifest, and Firefox removed the plug-in. Again, Firefox continues to function normally - but I would like to use VLC as-intended. All other (30+) add-ons and plug-ins I am running function normally.

Is there a solution for this problem?

Thanks!
David