I thought I’d have a read through the technical preview docs for SP2010 and came up against this problem:
I’ve seen this problem a few times before when tying to access .CHM files. It often happens when you download SDK documentation from the web. (Unsurprisingly since it’s a security feature designed to prevent downloaded content from causing mayhem on your PC!)
To fix it:
Find the file that you’re trying to view, in my case: SPPT2010TP.CHM
Right click then select Properties:
Hit the Unblock button
Re-open the file and all will be well in the world again.
If you we’re expecting some juicy info about 2010, I apologise! Once I’ve read through the docs I’ll post anything interesting that I discover.