hi, this is an important security feature in firefox, as flash versions with known vulnerabilities won't be executed (and therefore can't be exploited) by any website you may visit anymore. this may be an inconvenience but a huge gain for the security of the system that you're using and your data on it, as outdated plugins are a known infection vector for malware like cryptolocker viruses (real world example: https://blog.malwarebytes.org/malvert.../booby-trapped-hugo-boss-advert-spreads-cryptowall-ransomware/)

please activate flash manually on sites where you really need it until your IT is providing an updated version: Why do I have to click to activate plugins?

I agree with the security issue. Here is what happens. I update flash. Our corporate IS system sees that the version is not the same as the "official" version and begins to download the older version. That causes all browsers to close for the "update". After running for 20 minutes or so, it times out because Adobe won't allow down-versioning. Some time later, it tries again and this keeps up until I delete the new flash version. I know this is a corporate issue, but there must be some way to keep firefox from asking the same question about the update for almost every web site I visit. Is there some way to acknowledge only once?