Issue with Norton Security/AntiVirus "Intrusion Prevention" causing lockups.
This issue is happening with Norton Security/AntiVirus 220.127.116.11 on Windows 10 1903 (October/November/December patch levels). Sorry there's no error codes for Norton as Norton is the cause of the issue with other programmes.
I regularly transfer large files on my LAN from a Linux PC to a windows PC using SFTP (SSH File Transfer Protocal which uses SSH rather than standard FTP). The Linux PC runs the SSH/SFTP server and I connect to it with FileZilla FTP client on the Windows 10 PC.
When I've been transferring files, FileZilla and more often than not Windows itself freezes/lags/locks up which makes it difficult trying to load task manager to kill the FileZilla processes as the mouse is lagging, opening task manager takes a long time, clicking on a tab in task manager doesn't do anything for long periods of time.
This issue doesn't occur when connecting to a remote server where the limiting factor is my internet connection which is under a tenth the speed of my LAN connection. When transferring at 9MB/s (or ~70Mbit) everything seems to run normally. The issue occurs when doing high speed transfers over a LAN i.e. 1Gbit or 110-120MB/s.
The issue does not seem to occur when using standard (unencrypted) FTP although I only set that up to test as I will not run it for day to day use.
The issue also does not occur when using FileZilla to upload files to the Linux PC via SFTP. Uploads seem to run at normal speed with no lag/freezing/lockups. The issue only seems to occur when downloading from the Linux PC/server to the Windows client.
The reason I'm posting about this on a Norton forum is that I did a clean install on a spare SSD to try and see what the issue was and maybe narrow it down. Installing drivers etc and changing settings/installing programmes one thing at a time I finally got to installing Norton AntiVirus...and the issue started straight away.
I turned off functionality in Norton AntiVirus one thing at a time until the file transfers started behaving normally.
Turning off Intrusion Prevention entirely "resolves" the issue...although doesn't since it means you are turning off important core functionality of the security programme. Turning off sub settings such as App URL monitoring, Notifications, disabling Intrusion AutoBlock and disabling all Intrusion Signatures had no effect. The only way to get things working normally is to turn off Intrusion Prevention itself entirely.
But if I have Skype open (Windows programme, not the UWP/Windows Store version) or spotify or playing a flash video in a browser or watching an HTML5 YouTube video in chrome...everything works normally! Which is very strange, why would running any of those, which means more network activity, make everything else work normally?
With regards to the HTML5 Youtube video in chrome, while the video is playing file transfers run normally. If the video is paused and I open FileZilla to transfer a file then the lag occurs.
Neither turning off Intrusion Prevention or running skype/spotify/youtube videos all day is a good solution to this issue. Norton is seemingly interfering with normal usage and causing lockups...
Apologies for the long post but there was a lot of relevant information.
Thanks for any help you can provide.