When testing upgrade of Office365 on my RD host I got a problem opening office documents from desktop or documents that reside on a user profile disk.
Word will show the "starting" splash screen for 10-15 minutes and eventually do nothing then close. Same with Excel
If I copy the same documents to the users Home drive thats on the network, the document opens normally, as in super quick.
I tested this with Office 365 Enterprise on:
Current Channel (2108) = Problem
Monthly Enterprise (2107) = Problem
Semi-Annual Enterprise (2102) = No problem
Server OS is 2012 R2