QUESTION:

"The capture plugin is not showing up in my Safari on my MAC."

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ANSWER:

Okay, I've seen this problem twice before and this is what I suggested:

1) Try restarting the your computer.
2) If a simple restart doesn't work, try running this command in a Terminal window: /System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user