Anyone having issues with YouTube screwing up Safari? Everything's up to date, including Flash, and for some stupid reason out of the blue, when loaded a YouTube video, it chokes and freezes and makes Safari act up.

I have this very same issue that started a couple of week ago. The loading wheel spins and the audio of the video can be heard and then the video suddenly appears after a few seconds, but is jerky and stops and starts. A restart of my MBP will cure the problem for a couple of videos, but it creeps back in short order. If you try to close the Safari window when this happens, it pinwheels for a long time before it closes the window and at times a force quit is the only way out. Very frustrating.

I'm seeing that problem with all flash videos, not just YouTube. I suspect it was introduced in a Flash update, hopefully it'll be fixed soon.

UPDATE:
I went to the Adobe site this morning and was going to try and uninstall and reinstall Flash. When I clicked to download the uninstaller, a screen popped up that analyzed my MBP and notified me that my version of Flash was not properly installed. So I downloaded the uninstaller, ran it, then downloaded Flash installer and reinstalled it and everything works great now. All video plays smooth as a whistle so perhaps the fix is already done. Others may want to try the same method to see if it also cures their issue.

Thanks for the replies... I'll try to re-install Flash and see if that fixes it.

EDIT: Didn't work for me. If I try to load the same video, it freezes and stutters and I get the rainbow wheel.

Here's what I did:

Delete Safari using AppZapper or AppCleaner so it gets rid of all the plist files etc., then delete Java and uninstall Flash with the uninstaller from Adobe. Check your System Prefs to be sure it is gone.

Then download and install a fresh copy of Safari and Java from the Apple site, and Flash from Adobe. Then restart the computer. That cured my issue completely.