The following are known issues for Office for the web integration.
Known Issues integrating with Office for the web
#139: Business user flow: Office for the web does not load properly after user sign-in when third-party cookies are disabled
As part of the business user flow, users are asked to sign in using their Office 365 credentials. After sign-in, they're re-directed to the HostEditUrl. But if third-party cookies are disabled, the Office for the web application fails to load because the authentication cookie needed to verify the user has signed in successfully with O365 and it isn't sent along with the Office for the web iframe request.
Users must either allow third-party cookies or add
*.officeapps.live.com to their browsers cookie allow list.
In some browsers, like Safari, third-party cookies are disabled by default.
Also, browsers like Internet Explorer have a concept of zones, which can change how cookies are handled (among other things). Ensure all the sites in question are in the internet zone.
#143: PowerPoint Online: Download a Copy triggers browser pop-up blocker
In PowerPoint Online only, the Download a Copy action can trigger the browser's pop-up blocker. We're working on a fix for this issue.
#158: Office for the web fails to load files with characters in the name that are invalid in Windows
If a user's file name contains the following characters, the file won't open properly in Office for the web:
We're evaluating fixes for this problem. In the meantime, hosts should strip these characters from file names in order to open them in Office for the web.
#183: Creating new documents in Word Online results in two PutFile calls
When creating new files in Word Online, the WOPI host receives two PutFile requests from Office for the web instead of one.
Known issues integrating with Microsoft 365 for mobile
Microsoft 365 for mobile fails to load files with invalid characters in the file name, folder names, or user ID
These properties are affected:
To work around this issue, hosts should replace these characters with