Please follow instructions here: How do I quit Safari (or another browser/app) in OS X,
Mac has a feature to reopen previously open apps upon reboot. If you have this check-box selected it may very well be re-opening Safari when you reboot the system. Here is a screenshot of the dialog window (for a restart, but the shut-down is the same):
Have been messing with this problem for a couple of hours. Short story: go to this Adobe page Installation problems | Flash Player | Mac and use the link at the bottom. This will download a package that will let you install the latest Adobe Flash Player.
Longer story: there is a major difference in size between the "AdobeFlashPlayerInstaller_14_ltrosxd_aaa_aih.dmg" that you get from the regular Adode Flash Player website (1.2 mb) and the "install_flash_player_osx.dmg" that you from the above link (16.5 mb). My guess is that the link on the regular website is bad. It states that the download should be 15.7mb, but, as above, it was actually only 1.2 mb.
At least, this is what happened to me and what finally worked.
The link from the regular website is not bad. It is a shim installer that downloads and installs the Flash Player silently in the background.
Regardless if using the online (shim) installer or the full installer you point to, applications that use Flash Player need to be terminated for the installation to continue. While your post is helpful, it will not resolve the OP's issue as they still need to terminate Safari for the installation to complete.
I went through the "terminate Safari" processes as well. I did all of that, including uninstalling the previous version. Nothing worked with the download from the main site. I would get the disc image and click on it. I would then get the red "Install Adobe Flash Player" and click on that. I would get the black box that said "initializing." Nothing would happen with this until it said that the download was bad and that I needed to reinstall. I went through that process several time, including deleting the downloaded disc image that didn't work and redownloading a new disc image. No matter what I did, the results were the same...the downloaded disc image was not working.
I then started sniffing around the Adobe website and came across some trouble shooting instructions. I followed those, including right clicking on the "Install Adobe Flash Player" button to get to the "contents" folder. The instructions then told me to click on a folder, which was not there in what I had downloaded. I deleted what I downloaded and tried this process again, with the same results.
I only had success with the link on the bottom of the other Mac trouble-shooting page referenced in my post. Once I downloaded that package, I noticed the size difference between the two disc images. The last package worked like it was supposed to, and I finally got the updated Adobe Flash Player downloaded and operational. I could not get anything from the download from the Adobe Flash Player update website.
I have a mid-2011 MacBook Pro with an Intel Core i5. I've never had this much trouble updating Flash Player before. Since the link on the referenced troubleshooting page work like it should, and since all other previous updates worked like they should, I can only conclude that something must be wrong with the main Flash Player website link or package for this update to Flash Player 14.
Thanks for the reply.
Thanks for the additional details on your installation issue. We are aware of Mac users experiencing issues with the online shim installer. Unfortunately, we have not able to reproduce most of these issues. Obtaining the install log file for the online shim installer requires running the online shim installer from the Terminal with a debug argument. Most users are not comfortable working in the Terminal and just want to get Flash Player installed. We get that. However, without these install logs, we are unable to investigate the issues being reported.
Regarding the troubleshooting instructions to extract the PKG from the APP installer, this is for the full, offline, installer (downloaded from the installation help page), this is not for the online shim installer, which is why you didn't see it in the package you were downloading.
I understand your frustration and apologize. I'm glad you were able to get Flash Player installed with the full installer.
This worked perfectly for me and I have OS 10.9.4 on my iMac.