Hi I've been encountering issues with Sourcetree running incredibly slowly, with response times around 10 seconds. However I have noticed that if I temporarily disable my Avast shields Sourcetree becomes instantly responsive. I'm posting this because in my searches I have noticed a lot of people complaining about this issue and tampering with all sorts of settings with varying or marginal results.
Anyway I'm just curious to see if anyone else using Avast + Sourcetree has had a similar experience to me and possibly if they know why or to suggest a course of action short of changing Antivirus software that might make things a bit easier.
Interesting, I did as you said and could not find a box listed under E, instead I had the options "R" (Read) "W" (Write) and "X" (Execute). I assumed that the "E" you mentioned would likely also mean execute in this context. However, I have not noticed any difference in the issue using these instructions so I'm going to trust your judgement and assume I have not followed them correctly.
Another difference I have noticed is "Protectin FileSystem" is not an option on my components list, but instead "File System Shield" was the component in which I modified the exclusions.
Note in the screenshot I currently have my file shields disabled as I'm working on a project right now.
Pretty old thread but just in case someone is having the same issue you need to follow the steps described by @Carlo di Salvatore although the component is now called "Behaviour Shield".