Default font in outlook

FAST I/O DISALLOWED just means that a process is trying to access file data and the system doesn't have that data cached.

It's documented quite extensively in the fourth edition of Windows Internals by Mark Russinovich and David Solomon.

So in relation to the problem we were having it makes sense to see these FAST I/O DISALLOWED errors because the data wouldn't likely be cached.

We never managed to work out exactly what was causing the issues with the attachments.

A GPO can be used to set values/keys in the registry.

But consider it will be very easy for users to override the default font on each email (it might even be possible to automate this with a macro). So probably more important to educate users about what the standard is and why they should follow it.