I've been running into this issue since the latest patch update. Still haven't figured out a work around.
It's obviously related to not being able to r/w to the updater location which is in appdata. So windows may just say hey, no dont do that from there. So when I change the location to within the buddy folder and try to manually run the updater. The update keeps crashing on waiting for Exilebuddy Processes to end.
Edit: Yep, feel like an asshat. Totally overlooked it. I just turned off Windows Defender Live scan.
Start > Settings > Update & Security > Windows Defender > Real-Time Protection > Flip off.