A already had this problem in a former version (see here). The window freezes, if I try to do the upgrade in the backend (see enclosed screenshot). I had to reload the window in order to finally make it run. Not really inspiring confidence!
Are you manually uploading the files or running the upgrade check/install from the ACP? Might want to try the other way to see if it works. What browser are you using?
I updated to 2.1.8. Patch 1 today as well and it worked (with the Firefox Add-on "Greasemonkey" deactivated). The same applies to the latest update of the Ressource Manager.