With Nod32 enabled, the performance of Sage Line 50 is badly affected. With it disabled, Sage runs as normal. I started by excluding all the folders relating to Sage plus the network share (mapped to a drive) and it's folders - no change. Code: C:\Program Files\Sage\*.* C:\Program Files\Common Files\Sage Line50\*.* C:\Program Files\Common Files\Sage Report Designer 2007\*.* C:\Program Files\Common Files\Sage SBD\*.* C:\Program Files\Common Files\Sage SData\*.* C:\Program Files\Common Files\Sage Shared\*.* S:\ I then excluded the root of the OS (C:\) and the root of the network drive (S:\) and the network share for good measure. Still no change. Code: C:\*.* S:\*.* \\server\share\*.* Disabled the file scanning, everything back to normal! I can see in the task manager that, even with every file on the computer excluded and every file on the network drive excluded, ekrn.exe is still scanning during Sage operations which is leading to incredible slow downs. I also notice that if I look in the resource monitor, network usage goes through the roof, holding at around 90Mbps for around 10-15 seconds when I click on "new invoice" from a customer's record with real time scanning enabled. If you click "new invoice" with it disabled, there's a short blip of network activity and the new invoice loads almost instantly. If I disable real time scanning for network drives, the problem goes away. Vista SP2 client machines are running Nod32 V4 for Business, SBS 2003 server running Mail Security V4, Remote Administration Server and Console V4. All applications, drivers, etc. etc. etc. are up to date - this was a fresh install this morning. Advanced heuristics on file execution not enabled. Any advice would be much appreciated else I'll have to look for an alternative AV solution EDIT: To summarise the below posts, use the first lot of exclusions above plus C:\ProgramData\Sage\*.* and, providing the file server hosting the Sage account data has it's own AV scanner, turn off network file scanning on the clients and all should be speedy again. Not the best solution be seems to be the only one!