Hi Scott,
I don't know for sure that the speed/freezing issues are entirely caused by my AV software. But having had our IT support investigate the issue, they said that it was isolating and scanning each file every time ArcGIS pro refreshed (or in this case anytime I tried to edit the data, change symbology etc.) The problem appears to be worse when using layers from ArcGIS online or dropbox synced files. Most of our data is synced with dropbox (we're a small organisation and all work remotely) so this can't be avoided. I experience none of these issues when carrying out exactly the same operations in ArcMap... The AV software is Sophos Endpoint. I believe it's possible to set up exceptions, but our organisation has been victim to several attempted cyber attacks recently and our IT contractors are hesitant to do this.
I've submitted a support case so hoping to find a solution.
Thanks!
Anneka France
Technical Manager at The Rivers Trust