SSO not working in Office apps

[gshaw]

Until now our SSO for Office 365 has been working perfectly but noticed an odd issue that's appeared in the last week or so:

 

• When on a domain PC Microsoft Office detects that we're running SSO and automatically signs the account into OneDrive for Business and SharePoint, which then appear in the Locations list when going to File > Open.
  
• However since last week any accounts that already have a profile on the machine now have a sign-in error in the top corner of the screen
  
• New profiles don't auto sign in any more and only show the default OneDrive and local options.
  
• If I try to add locations manually the process fails with "invalid account" error
  
• The only way to get the O365 account to sign in is to use the Switch Account button, then Add Account and enter username and password again
  

 

Has anyone been experiencing anything similar?