I have Jetpack installed on multiple sites, some of which are multi-site installs. I have never had a problem with it until I tried updating it on one of my multi-site installs and it just hangs. I've tried re-installing WordPress, deleting Jetpack and reinstalling, etc. The only way I can get it to work is to literally delete the files in the plugins directory and copy the newest version in there myself. Thoughts? Suggestions?