I have bittorrentsync (latest) installed on 3 different machines (all windows 7). Two of them are fine, and for example when I drop a file in to a sync folder they do not slow down at all or it is barely noticeable. However, on this 3rd machine, while BTSync is running windows explorer becomes very unresponsive. It does not appear to be taking up any CPU time, the machine is mostly idle. If I exit BTSync, the issue stops. It only appears to impact the windows explorer process. For example, I might have several programs running - browsers, outlook, etc. and I can alt-tab and use them without issue full speed. It's only when I try to get to the start menu, file explorer or similar when it's VERY slow or unresponsive. I do not see anything strange in the software itself, no strange error messages for example. I have tweaked settings on the machines to try to help, for example use tcp, not to use encryption on lan and have tried the hard drive high priority vs. low priority with no difference. I checked and all my ata devices say ultra dma. This is an recent i7 machine with 24 gigs ram. Any ideas on what I can look at?