heavy network usage

[TopDon]

I'm having issues with a pair of scenes, a living room and a bedroom that are incredibly slow to work on..  The culprit appears to be heavy network usage (windows 10 says a pretty constant 50mb down once the scene is open)
All textures and proxies are coming from a shared NAS.
THis is same in in Max 2014 upwards it seems..
I cant see what the scene is doing, that it needs to constantly bother the network like this.. I'd expect it at render time and saving etc, but not just sitting there..
Any thoughts or suggestions welcome..

[maru]

Random thoughts:
-Antivirus/firewall - even Windows Defender, MS Security Essentials, etc - they may be checking network traffic all the time for no reason. This is common. The first step to verify if this is the culprit is to temporarily disable the AV software and see if there is any change.
-CoronaBitmap or MaxBitmap - can you try switching between these two? You can easily do this with the converter script. Just convert all the bitmaps in your scene to CoronaBitmap - check if it's the same, then convert all to 3ds Max Bitmap - check if it's the same.