Someone sent me this information about issues when you install a trial version of Office 365 E3 SKU which includes Office Professional Plus (which is also a trial version during this period).
Seems to be that when the trial period expires the Office Professional Plus that came with the Office 365 trial SKU goes into “reduced functionality mode” because it doesn’t activate (being a trial license after all). You can use the osaui.exe tool if this happens to re-license the product (one the license is valid):
My general advice to people is that now Office 365 is available on a month by month basis that it really isn’t worth going on a trial, simply buy it. In short do your evaluation of Office 365 before you sign up as converting from a trial version to anything but that trial version can be a little painful sometimes.