I noticed this in 4.2.58 as well: Office 2010 documents open incredibly slowly over the network using the default configuration, sometimes incurring a delay of twenty seconds or longer per document opened (even very small files.) I still haven't nailed down which setting eliminates this delay, but the delay appears to be caused by the AV settings on the machine hosting the particular file. This is repeatable by disabling the AV on the host machine and testing. Unchecking 'scan all files' under Real-time file system protection -> Threatsense engine parameter Setup -> Extensions appears to remove this delay, although this may just disable scanning of Office 2010 documents altogether, as the new 'docx' and other formats are not included in the default list of extensions. Has anyone found a good configuration for networked environments where computers are used as both hosts and clients for different file stores, while still allowing for scanning of Office 2010 documents over the network?