What version of Premiere Elements on Window 10 assumed 64 bit?
I have Windows 10 64 bit on two of my computer, and my impression is the Premiere Elements successes and failures are the same before and after the upgrade to Windows 10.
How are do you get in the Premiere Elements built in YouTube feature? Assuming that you have Premiere Elements 11, 12, or 13, how far do you get into the built in YouTube feature when the problem presents? Did you see "presets downloading" when you used the feature for the first time?
What error message(s) do you get associated with the problem?
For troubleshooting purposes, can you export your Timeline content to a file (AVCHD.mp4) and then upload that file to YouTube at the YouTube web site?
What is the duration and estimated file size of the upload that fails in Premiere Elements - under 2.2 GB/15 minutes?
Several are having problems with Publish+Share and the Online Services. Recently there was a generalized YouTube HTTP 500 error that affected most if not all. That appeared to have been fixed within a day or so, assumed by YouTube.
Please give more details so that we can decide what next.